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Amaranthus yields could benefit from our growing understanding of the genetic variability within and among individual species of local germplasm collections. Thirty-seven Amaranthus accessions representing three different species were evaluated for seed yield and yield components across two seasons. The objectives were to characterize the genetic variability of seed yield and its components across species and determine relationships among seed yield and its components by phenotypic correlation. Significant differences (P

We investigated the effect of poultry manure (PM) on the occurrence and early growth of Monochoria vaginalis in relation to soil solution electrical conductivity (SSEC). PM was applied at rates corresponding to 0 g of nitrogen (N) m−2 (PM-0), 1 g N m−2 (PM-1), 3 g N m−2 (PM-3), and 5 g N m−2 (PM-5). At 7 d post-seeding, the soil solution was sampled to measure EC, and also the emergence and growth of M. vaginalis were evaluated. The emergence rate of M. vaginalis decreased with increasing application rate of PM and SSEC. SSEC was significantly negatively correlated with the emergence rate of M. vaginalis seedlings. The average leaf number and length of M. vaginalis did not differ between PM-0, PM-1, and PM-3, but were significantly lower in PM-5. In summary, PM would allow to better control the emergence and early growth of M. vaginalis.

Sorghum cultivar ‘Kazetachi’ has a unique internode length pattern, with a wavy shape that changes depending on the cultivation environment. It is regarded as a suitable material for analyzing the environmental factors affecting internode elongation. This study was conducted to clarify the relation between the final internode length at harvest and the increment of stem growth to establish a method to elucidate stem growth during the growing season. To confirm the internode elongation pattern, we sampled plants when each leaf had just expanded. The leaf number, plant length, and collar height of plants in the field were measured during the growing season. The internode elongation pattern of ‘Kazetachi’ resembled that reported in sweet sorghum, indicating that the elongation period of each internode can be estimated by recording the leaf number during the growing period. By measuring the plant length and the collar height as an index of stem growth, we can easily estimate the rapid elongation period of internode, which can be a peak or a trough in the internode length pattern during the growing period. The collar height during the growing period can be estimated by measuring the leaf number in the growth stage and recording the length of internodes and leaf sheaths at harvest. Even the plant length can be estimated by adding the leaf blade length to these traits. However, the collar height seemed to be a better index of stem growth than the plant length.

SummaryWhen maintained continuously under long-day (non-inductive) photoperiodic conditions, chrysanthemum (Chrysanthemum morifolium Ramat.), a short-day plant, eventually initiates flower buds. This floral initiation is termed ‘premature budding’ in commercial chrysanthemum production. Premature budding, which reduces cut-flower quality, is often observed in summer-to-autumn-flowering cultivars. The timing of flower initiation under non-inductive photoperiods depends on the number of leaves that a plant has formed below the terminal flower bud. This leaf number indicates whether a cultivar will form flower buds prematurely during a non-inductive photoperiod. Two summer-flowering, ten summer-to-autumn-flowering, and six autumn-flowering chrysanthemum cultivars were grown under controlled conditions to measure the number of leaves produced under a non-inductive photoperiod with a night-break. The average number of leaves per plant ranged from 13.8 for ‘Tasogare’, to 69.1 for ‘Furamu’. These data can be use...

The objective of this study was to determine the effects of imazethapyr on soil microbial communities combined with its effect on soybean growth. A short-term field experiment was conducted, and imazethapyr was applied to the soil at three different doses [1-fold, 10-fold, and 50-fold of the recommended field rate (H1, H10, H50)] during the soybean seedling period (with two leaves). Soil sampling was performed after 1, 7, 30, 60, 90, and 120 days of application to determine the imazethapyr concentration and microbial community structure by investigating phospholipid fatty acids (PLFA) and microbial biomass carbon (MBC). The half-lives of the imazethapyr in the field soil varied from 30.1 to 43.3 days. Imazethapyr at H1 was innocuous to soybean plants, but imazethapyr at H10 and H50 led to a significant inhibition in soybean plant height and leaf number. The soil MBC, total PLFA, and bacterial PLFA were decreased by the application of imazethapyr during the initial period and could recover by the end of the experiment. The ratio of Gram-negative/Gram-positive (GN/GP) bacteria during the three treatments went through increases and decreases, and then recovered at the end of the experiment. The fungal PLFA of all three treatments increased during the initial period and then declined, and only the fungal PLFA at H50 recovered by the end of the treatment. A principal component analysis (PCA) of the PLFA clearly separated the treatments and sampling times, and the results demonstrate that imazethapyr alters the microbial community structure. This is the first systemic study reporting the effects of imazethapyr on the soil microbial community structure under soybean field conditions.

SummaryChrysanthemum (Chrysanthemum morifolium Ramat.) is a short-day plant; however, flowering is eventually initiated under non-inductive long-day or night-break conditions. When using Summer-to-Autumn-flowering cultivars, such flowering is undesirable for stable horticultural production, particularly for Summer cropping, because of the short length of the cut flower, the formation of a crown bud, and the development of a branched spray of flowers. Under non-inductive conditions, flowering depends on the number of leaves that form below the terminal flower bud (i.e., the long-day leaf number). Long-day leaf numbers varied among cultivars in this study. ‘Nagano Queen’ showed a seasonal change in long-day leaf number, being high in Spring and decreasing in Summer. In addition, rooted cuttings under night-break conditions initiated very early flowering. Here, we show how exposure to prolonged Winter cold influenced long-day leaf number, and its inhibitory effect on flowering. Cold pre-treatments inhibited ...

Five upland cotton varieties (Gossypium hirsutum L.) (Aleppo 118, Aleppo 33/1, Aleppo 90, Raqqa 5, and Deir-Ezzor 22) were evaluated under different salinity indices [0, 50, 100, and 200 mM sodium chloride (NaCl)] for 56 days. During the course of the experiment, plant size (HT), leaf number (LN) and leaf area (LA), chlorophyll SPAD (Soil Plant Analyses Development), chlorophyll (Chl) a and b content, and osmotic potential were measured in both control and salt-stressed plants for all tested varieties. Salt-stress application reduced the HT and LN of all varieties, whereas LA decreased as salinity level increased for all tested varieties comapared to their respective control expect for Deir-Ezzor 22 variety. Our data showed that LA, Chl a and b, and chlorophyll SPAD can be used to discriminate between salt-tolerant varieties and salt-sensitive ones. In this respect, Deir-Ezzor 22 variety differed by showing high salt tolerance relative to Aleppo 118 and Aleppo 33/1 varieties. Therefore, this investigation...

The growth, morphological traits, and biomass accumulation and allocation pattern of Vallisneria natans grown from buds were observed in a non-rooted suspended state in the laboratory. Submersed anchored V. natans were about 229% higher in height, 208% higher in leaf number, 719% greater in total root length, 64% higher in lacunal root volume, and 1473% greater in total biomass dry weight compared with suspended V. natans. However, insignificant differences existed in root diameter, specific root length, and biomass allocation patterns. These results indicate that when V. natans is not anchored to a substrate in the normal mode, the growth will be markedly suppressed.

The tolerance of different coffee-plant progenies to zinc (Zn) deficiency was studied in a green house experiment arranged in a completely randomized design, in a 14 × 2 factorial scheme (14 progenies and two Zn concentrations), with four replications. Coffee-plant seedlings were grown for ten months in nutritive solution with or without Zn. There were evaluated for growth characteristics, zinc concentrations, and zinc requirement. The grouping involving growth characteristics allowed discriminating the progeny ‘UFV 4066-3’ as highly zinc-demanding and ‘IAC 4376-5’ as low zinc-demanding. The data on plant dry matter and zinc accumulation showed that the progenies ‘IAC 4376-5’ and ‘UFV 4066-5’ had low zinc requirement when ‘Caturra Amarelo 1’, ‘UFV 4066-3’, ‘Caturra Amarelo 2’ and ‘Caturra Vermelho 2’ had high zinc requirement. Leaf area reduction (%), leaf number, active zinc content in completely expanded leaves and total zinc in roots were the variables of highest relative importance in discriminating c...

The response of flea beetles (Podagrica spp.) to visual cues produced by differently coloured polyethylene films, and the performance of okra plants grown under shades, were studied in Nigeria. In the first of our experiments, factorial combinations of seven shade contrasts and two okra varieties grown in pots were laid out in a completely randomized design. A second experiment comprised five differently coloured plastic water trap bowls laid out in the field in a randomized complete block design, with four replications. Okra plants covered with yellow polyethylene films consistently attracted significantly higher numbers of adult Podagrica than plants grown under other-coloured films. Plant height, stem diameter, leaf number and size were significantly higher under red polyethylene covers. The number of fruits harvested under the transparent (clear) cover was significantly higher than the number harvested under red, green or blue film polyethylene covers. Also, the yellow-coloured plastic water trap bowl...

To study the differences in growth and potassium (K)–use efficiency of two different K-use-efficiency cotton genotypes, a pot experiment was conducted in 2007. Experimental materials include two cotton genotypes (HG103 and LG122) and two K application levels (0 and 0.23 g kg–1 soil). The initial dates of various growth stages, plant heights, numbers of leaves, squares, and bolls, and the amount of litter during the whole growing season were recorded. The distribution and accumulation of dry matter and K content in various organs were measured to compare the differences in K-use efficiency. Significant differences (P < 0.05) between the two genotypes and K levels were found in initial bolling time. At the reproductive growth stage, the plant heights and leaf number of HG103 were less than those of LG122. Greater numbers of squares and bolls were recorded from HG103 than LG122 with K application. Significant differences (P < 0.05) existed in dry matter and K contents in each organ in the two genotypes and K...

In sweet sorghum, which is a potential biomass crop, the diameter of internode is an important component of stem yield. However, the thickening of successive internodes is poorly understood. The objective of this study was to clarify the relationship between the thickening of successive internodes using the age indicated by the leaf number on the main stem (AL) as a time scale. Furthermore, the relationship between the elongating and thickening period of successive internodes along the stem was analyzed. Internodes were collected from AL3, when the 3rd leaf had just expanded above the 2nd leaf sheath, to AL17, and at 9 weeks after heading as final harvest. Although the internode thickening patterns based on AL could not be combined into one or a few patterns, a significant correlation (P

Municipal solid waste compost (MSWC) has been reported to improve plant development and yield. Additional information is needed to determine the efficacy of use of MSWC for short-season crops including lettuce (Lactuca sativa L.). The experiment was conducted at the experimental field of the Agronomy Faculty, University of Guilan, Rasht, Iran, in 2008, to determine the effect of MSWC on lettuce, cv. Baboli, growth, yield, and yield components. The MSWC was applied at 0, 25, 50, 75, and 100 Mg·ha−1. Compost at 100 Mg·ha−1 produced a higher yield than the other treatments. Significant differences were found in plant weight and leaf number. Correlation analysis indicated that plant weight was correlated with yield and leaf number and yield was correlated with leaf number.

High salinity in soil is one of the major factors limiting plant growth and productivity. Strawberries are very sensitive to salinity (Larson, 1994), and salinity reduces leaf number, leaf area, sh...

SummaryExperiments were conducted in controlled environment conditions in the UK and under tropical field conditions in Sri Lanka to determine the effects of plant size in similarly aged onion seedlings at transplanting on their subsequent growth and development. Results indicated that the size at transplanting, in terms of leaf number, leaf area and total weight, continues to affect the size of the plant until maturity. Under low light conditions (maximum PAR levels of 800 mmol m±2 s±1), and low night temperatures (minimum 118C) in the UK, transplant size was negatively correlated with time to onset of bulbing and maturity, and positively correlated with bulb weight, and percentage contribution from scale leaves to total bulb weight. However, under high light intensities (PAR level of >1500 mmol m±2 s±1) and high night temperatures (>208C) in Sri Lanka, transplant size was positively correlated with time to onset of bulbing and maturity, percentage of thick neck bulbs, and yield of good quality bulbs. It...

The changes in growth, dry matter productivity and yielding ability in the course of domestication from O. breviligulata to African rice (O. glaberrima) were examined. Between the two rice species, differences were hardly detected in plant height, culm length and final leaf number, although O. breviligulata had a wider variation of these characteristics as compared with African rice. The shorter strains tended to produce more tillers at the maximum tiller number stage, and the high tillering capacity was correlated with a low percentage of productive tillers, although the strains having a small number of grains per head showed a high percentage of productive tillers, in both species. No significant difference was detected between the two species in straw weight at maturity, and the differences in straw weight among strains were attributed to the differences in days required from transplanting to heading and to plant height. No significant difference between the two species was observed in top and total weights. The grain number per head was conversely related with panicle number in both species. Although the percentage of ripened grain tended to be slightly lower in O. breviligulata than in African rice, this may be attributed partly to the difference in grain number per hill. Single grain weight in O. breviligulata was nearly equal to that in African rice. These results suggest that agronomic traits such as growth, dry matter productivity and yielding ability have been changed only slightly in the course of domestication from O. breviligulata to African rice.

SummaryEffects of photoperiod on flowering, measured as days to macroscopic flower visibility and as leaf number below the terminal inflorescence, were studied in three cultivars of cineraria, Cindy Blue, Cindy Pink and Cindy Dark Red. Short photoperiods accelerated, and long photoperiods delayed, but did not prevent, flower initiation in plants grown under commercial temperature regimes (8–14°C) in glasshouse conditions. The critical photoperiod for flower initiation was 12 h, at and below which plants produced the fewest leaves below the flowers. In cvs Cindy Blue and Cindy Pink, the ceiling photoperiod was 16 h, at and above which plants produced their maximum final leaf number. The rates of progress to flower initiation and to flower visibility were shown to be faster in plants grown under 8–12 h photoperiods and both rates decreased approximately linearly as photoperiod increased from 12 to 16 h in cvs Cindy Blue and Cindy Pink. There was no “minimum number” of short-day cycles required for flower in...

SummaryEffects of temperatures and durations of temperature treatments on flower induction were studied in cineraria cv. Cindy Blue grown in controlled environments. The earliest flower induction, recorded as the fewest leaves below the flower, was observed as 16–17 leaves initiated in non-juvenile plants that had been chilled at 5–7°C for 3–5 weeks as compared with 30–33 in plants grown throughout at 24°C. Plants demonstrated a true quantitative vernalization response in that flowering was delayed but not prevented by higher temperatures and further leaves were initiated below the flower after chilling had ended. The rate of progress to flower induction, measured as the reciprocal of leaf number below the flower, was shown to relate linearly to temperature. This enabled the base, optimum and maximum temperatures for vernalization to be derived respectively as –0.3, 5.9 and 15.8°C, where the base temperature corresponded to the rate at which the unvernalized plants would progress to flower induction. Rate...

Conventional strawberry (Fragaria ananassa Duch. cv. Chandler) production was compared with production undergoing conversion to certified organic management in a three-year, replicated, on- farm study. Plant vegetative development, measured as leaf number, leaf area, and vegetative biomass, decreased in the organic production system compared to the conventional system. Developmental differences were less significant in the third year of the study. Reproductive development, measured as number of flower buds, open flowers, and immature fruit, as well as total reproductive biomass, was also lower in the organic system. The timing and degree of difference in responses studied varied over the course of the study. The percent of total berries produced which were not marketable was larger in the conventional system in the second and third years of the study. Marketable fruit yield was consistently lower in the organic plots, but the margin of difference decreased over the course of the study from 39% to...

Grapevine cuttings induced to retain flowers by the Mullins technique were treated with plant growth regulators (PGRs) in various combinations or at different concentrations. Gibberellin A3 (GA3) at 100 ppm increased flower number, inflorescence branching, curvature and length of the rachis, but decreased leaf number. Adding kinetin (300 ppm) to GA3 eliminated the effect on flower number and leaf number. Indole acetic acid (1AA) reduced flower number and curvature, and also reduced the GA3-promoted increase of flower number. IAA reduced rachis branching and length. GA4 and benzyIaminopurine (BAP) generally had similar effects to GA3 and kinetin. Some differences and responses to PGR concentrations are presented and discussed.

Rooting and survival trials on cuttings of Cotinus coggygria cv. Royal Purple were carried out in two successive years following stock plant etiolation. Two clones were used which differed in age and source, clone SB stock plants were six years old, clone LP one year old. Etiolated SB shoots taken in May/June of each year showed a higher rooting percentage than those of control plants. The rooting percentage of control LP stock plants was higher than SB, and etiolation did not enhance this. Cuttings from both clones were difficult to root later in the season. The growth rate of etiolated SB cuttings, as indicated by lateral extension and leaf number was significantly greater than control cuttings in both seasons. In contrast there was no significant difference in the growth rate of LP cuttings taken in June. The survival of etiolated SB cuttings taken in May of the first season was significantly higher than that of control cuttings. A similar enhanced survival was recorded in the following year with etiol...

One hundred and fifty-eight cultivars and breeding lines of white clover were grown in four trials to determine which leaf and stolon characters gave the best prediction of clover content in a mixed species sward. Stepwise regression analysis was used and showed that in a rotationally grazed sward leaf number and leaf size, rather than stolon growing point density, were the best predictors of proportion of clover in swards.

Young tomato plants were treated with foliar sprays and root applications of aqueous solutions of methanol and ethanol. Concentrations ranged from 5 to 20% v/v. Root applications caused severe plant damage. In contrast foliar sprays resulted in significant growth stimulation. Both alcohols increased leaf and stem fresh and dry weights with the maximum increases at the highest concentrations tested. Methanol produced a greater increase in stem length and stem fresh and dry weights than ethanol. There was no signficant difference between the alcohols in terms of leaf weights or leaf number.

Stress has a negative impact on crop yield by altering a gain in biomass and affecting seed set. Recent reports suggest that exposure to stress also influences the response of the progeny. In this paper, we analyzed seed size, leaf size, bolting time and transposon expression in 2 consecutive generations of Arabidopsis thaliana plants exposed to moderate UV-C stress. Since previous reports suggested a potential role of Dicer-like (DCL) proteins in the establishment of transgenerational response, we used dcl2, dcl3 and dcl4 mutants in parallel with wild-type plants. These studies revealed that leaf number decreased in the progeny of UV-C stressed plants, and bolting occurred later. Transposons were also re-activated in the progeny of stressed plants. Changes in the dcl mutants were less prominent than in wild-type plants. DCL2 and DCL3 appeared to be more important in the transgenerational stress memory than DCL4 because transgenerational changes were less profound in the dcl2 and dcl3 mutants.

The purpose of this study is to obtain a comparative assessment of dihaploide lines and oriental tobacco varieties for number of genetic parameters applying the combinatory approach to diallel analysis. Two basic morphological traits “plant height” and “leaf number” are investigated. The conclusions valid for both the dihaploid varieties and dihaploid lines are that dominance is the basic inheritance type of the traits and the dihaploid lines arc more stable in some aspects.

Let G be a finite connected graph with minimum degree δ > 4. The leaf number L(G) of G is defined as the maximum number of leaf vertices contained in a spanning tree of G. We show that if δ ≥ L(G) ...

Tetraphis geniculata, of North American origin, grown in a north-facing glasshouse in Britain, showed marked seasonality in the duration of protonemal growth before the appearance of thalloid protonemal appendages and shoot buds, in the number of thalloid appendages formed, in the variation in the number of leaves borne on shoots and in the production of gemma-cups. The plastochron scale was used as a measure of earliness in the production of gemma-cups. Shoots formed early in the year, following a prolonged protonemal phase, had a low average leaf number but later in the year, when the protonemal phase was reduced, the average leaf-number was increased. In this period of the year leaf-number varied with temperature; the higher the temperature, the higher the average leaf-number. When the average maximum monthly temperature in midsummer was in the range 23°–28.5°C there was complete suppression of the development of gemma-cups and therefore a prolonged period of vegetative growth.

SummaryThe effect of a soil application of paclobutrazol at 4 kg ha−1 was assessed on the water use and growth of micropropagated rootstocks using M25 apple and Colt cherry rootstocks as test plants. To assess long term effects the M25 stocks were treated with paclobutrazol and, two months later, transferred to temperatures of 20° or 30°. To assess the immediate effects the Colt stocks were treated immediately following transfer to these temperatures. Paclobutrazol reduced M25 growth with effects, greatest on leaf number and stem weight, larger at 30° than at 20°. During a 14-day experimental period Colt growth was unaffected. In both cultivars total water use and transpiration were reduced by the paclobutrazol treatment. In cherry the effects of paclobutrazol on transpiration were apparent within two days of treatment. In both species water inflow per unit root length was reduced by the paclobutrazol treatment. In apple the effect of paclobutrazol on water use was greater at 20° than at 30°.

SummaryThe effects of temperature on the growth and hearting of butterhead lettuce cv Cobham Green were investigated in two experiments which used respectively a range of sowing dates and soil mulching treatments to provide different soil temperatures. In both experiments the rate of seedling emergence was directly related to mean soil temperature, and in the sowing date experiment alone the early relative growth rate of the crop was positively related to mean soil temperature but not related to air temperature. There were relationships between leaf number and soil temperature 2 cm deep (measured on an accumulated day-degree scale above 0 °C) which were described by two separate straight lines with different slopes, one for data up to and one for data beyond ten leaves, the latter having a higher rate of leaf production. Lettuces sown in mid-May, when the soil temperature was 20 °C, had heavier heads at maturity than those sown earlier or later, but there was no relationship between head weight and early ...

SummaryThe effects of day-length and light intensity on the growth rate and leaf number of an early (Pink Ice) and a late (Orchid Rocket) flowering variety of Antirrhinum majus L. have been investigated. Growth rate, as determined by plant height or dry-weight increase, was greater for Pink Ice in all instances. When the two varieties were grown under similar conditions, the leaf numbers prior to flowering attained by Orchid Rocket were always greater than those of Pink Ice. With high light intensity the long-day (LD) responses of both varieties were characterized by leaf numbers which were on average 30 leaves less than the numbers found on plants grown in short days (SD) at high light intensity. Pink Ice exhibited this photoperiodic response to LD irrespective of whether the light intensity was high (26,000 lux) or low (6000 lux), whereas the leaf number of Orchid Rocket only declined in LD when the intensity was high. Plants of this variety grown in low light LD had leaf numbers similar to plants maint...

Under low available soil N conditions, leaf area and leaf number at five sampling stages were strongly correlated with shoot weight in cowpea. Leaf area determination is proposed as a simple method for the identification of superior genotypes when breeding for enhanced N-fixation in cowpea.

SummaryTwo experiments studied the effect of transplanting plants of different sizes of cauliflower cv All The Year Round—Lero on the time of curd initiation, the growth of plant parts and the extent of buttoning, defined here as the production of small unmarketable curds less than 9 cm in diameter. Larger plants, transplanted later, produced more buttons but did not initiate curds earlier. It was not necessary for a plant to have initiated a curd before transplanting in order to produce a button. Larger plants at transplanting had a lower weight of leaf than smaller plants after curd initiation and consequently produced smaller leaves, so that curds were smaller when exposed and were therefore classed as buttons. An increase in the amount of buttoning with later transplanting occurred irrespective of whether the relative growth rates of plant parts remained proportional. It is suggested that if transplanting has been delayed, holding plants in a cold store once they have reached a specific leaf number wo...

SummaryA single foliar application of 2, 4 or 6% urea solution to ber cv Banarasi Karaka just before blooming in September significantly improved shoot growth, leaf number, area and weight, the best results being obtained following treatment with 4 or 6 % solutions. Flower number, fruit set and fruit retention were better in nitrogen-supplied plants. The size of the fruits and yield per tree increased with increasing concentration of urea and the highest yield (61 % greater than control) was recorded following 6 % spray treatment.

SummaryVirus-tested stocks of Narcissus pseudonarcissus cv. Carlton were compared in the field with commercial stocks which were at least 97% free from plants with visually obvious virus symptoms. Despite planting bulbs of similar weight and apparently uniform anatomical structure the number of growing points in the comparative stocks sometimes differed depending on the locality in which the bulbs were produced. Consequently, leaf number in year one, which is related to the number of growing points was used to adjust flower and bulb yield. After adjustment where necessary, the mean bulb yield of virus-tested stocks was 9-20% greater than that of commercial stocks. Increased bulb yield of virus-tested compared with visually healthy commercial stocks resulted from greater mean bulb weight. Virus infection apparently had no effect on bulb number. Virus-tested stocks flowered three to four days earlier than the commercial stocks but no clear differences in flower quality or number were detected.

SummaryRooted cuttings of twelve cultivare of Chrysanthemum morifolium, a short-day plant, were grown exclusively in long days in three consecutive experiments. The terminal and axillary apical meristems of all cultivars eventually initiated flower buds, although their further development was inhibited in long days and they did not reach anthesis. The period of vegetative growth was quantified in terms of the numbers of leaves and bracts initiated by each meristem prior to flower initiation. This number varied between cultivars and between experiments, but when the cultivars were ranked in order of leaf number, their relative positions were similar in each experiment. The rate of leaf initiation also varied between cultivars, but was not correlated with the number of leaves formed below the flower, from which it was estimated that the time of flower initiation also varied with cultivar.It was concluded that flower initiation in the chrysanthemum in long days is inevitable, with the time of initiation depe...

SummaryThe optimum leaf number: fruit ratio in various mango cuitivars was sought by isolating individual fruits with known numbers of supporting leaves by shoot girdling. 14CO2 feeding experiments showed a higher rate of carbon fixation in the leaves of girdled shoots than of control shoots but the translocation of 14C assimilates to the developing fruits on the girdled and control shoots was comparable. Starch accumulation in the leaves was reduced by shoot girdling. The stomatal resistance of the leaves of girdled shoots was comparable to that of leaves on control shoots. In all the cuitivars studied it was observed that 30 leaves, the maximum available on a shoot, could not support the growth of a single fruit to normal size. The results also show that fruit development depends not only on the current assimilates but also to a great extent on reserves. The utilization of reserve metabolites from vegetative organs during the ‘on’ year could be a contributing factor towards biennial and erratic bearing.

SummaryRooted cuttings of Dendranthema morifolium (Ramat.) Tzvelev (Chrysanthemum morifolium Ramat.) cvs Polaris and Bright Golden Anne were treated with the growth regulator 2-chloroethylphosphonic acid (ethephon) by applying a 10 μl drop containing 10 g l−1 a.i. to either a leaf or the apical bud, or both, or to different locations on the stem. Plants were either defoliated throughout the experiment, except for the treated (or control) leaf, or none of the leaves were removed. Plants were grown under short days and the effects of treatment assessed approximately four weeks later. Irrespective of the site of application, a single drop of ethephon increased leaf number, delayed time of flower initiation, reduced stem elongation and reduced apical dominance. The effect of ethephon was generally greater when the application site was closer to the apical bud rather than to a leaf. Application to the stem close to the apex was more effective than application to the base. Defoliating plants to one leaf resulte...

SummaryUnfeathered maiden trees of apple Stark Earliest (syn. Scarlet Pimpernel) were pruned back in winter to a height of 70 cm. The following spring five shoots were allowed to grow out, the others being removed. When the leading shoots were about 12 cm. long the trees were sprayed once with various concentrations of GA, TIBA, CCC and B.9 (see below), other trees being left unsprayed as controls. Subsequent effects on shoot growth were analysed in terms of leaf number and internode length. Apical dominance was destroyed or greatly reduced by GA (200 p.p.m.), TIBA (200 p.p.m.) and CCC (5,000 p.p.m.) and these substances all increased leaf number on the lower shoots. B.9 (2,000 p.p.m.) had no effect on apical dominance. TIBA, CCC and B.9 reduced mean internode length on all shoots, whereas GA increased internode length on the lower shoots only.CCC caused only a temporary check to growth, but the growth-retarding effects of B.9 and TIBA persisted throughout the growing season. The possible mode of action o...

As strains of Verticillium with increased pathogenicity had originated in several crops and serious outbreaks of Verticillium dahliae Kleb. had occurred in New Zealand tobacco (Nicotiana tabacum L.), isolates from four different fields were compared for virulence in inoculated field trials. No significant differences were found. In the field the growth of infected tobacco was retarded, final leaf number increased, and internode length was shortened. Eight weeks after inoculation 93 percent of the plants showed some symptoms, whereas only 5 percent of uninoculated plants had symptoms. After 15 weeks the percentages of visibly affected plants were 100 and 68.5 respectively. As leaf numbers increased from 6 to 14 the proportion of leaves with symptoms diminished, but it increased rapidly after the plants had flowered.

In a field experiment Hilgendorf wheat was found to initiate and produce ears earlier than Aotea, Arawa, and Cross Seven. Under controlled conditions none of the varieties tested showed an obligatory requirement for vernalisation, although Hilgendorf responded more strongly than the other wheats. Vernalisation caused ears to be initiated earlier and at a lower leaf number provided plants were exposed subsequently to continuous light or 14-hour days; in a to-hour day it had no effect. The length of the photoperiod influenced time to initiation and ear emergence as well as the number of leaves appearing at those stages. All varieties flowered in short days (10 hours), although only after 18-19 weeks from sowing. The field performance of wheat is examined on the basis of results obtained under controlled conditions.

Summary A study was undertaken for perennial ryegrass, Italian ryegrass, cocksfoot, and timothy, of the floral initiation, ear emergence, leaf number at ear emergence, and percentage of fertile tillers with dates of origin between May 1958 and February 1959. The influence of two levels of nitrogen was examined. Despite large ranges in their time of origin, winter and earlyspring tillers of perennial ryegrass, Italian ryegrass, and timothy all initiated floral primordia within a relatively short period. Ear emergence followed the same pattern. Mean leaf number at ear emergence decreased with tillers of later origin to minima of 6 for perennial ryegrass, 7 for Italian ryegrass, 9 for cocksfoot, and I+ for timothy. In cocksfoot and timothy the percentage of fertile tillers was high only for those formed before mid winter, whereas in perennial ryegrass and Italian ryegrass the percentage remained high even for tillers formed up to late spring. High nitrogen promoted earlier floral initiation and ear emergence...

Effects of 4 rates each of ancymidol and chlorethephon applied in factorial combination as drenches were measured on plant height, leaf number and size, and rooting of balsam. All treatment combinations reduced plant heights except the low rate of each chemical (0.25 mg/pot ancymidol and 10 mg/pot chlorethephon) applied singly. Leaf number was unaffected by treatment, but leaf size was reduced. Rooting, as measured by fresh weight, was improved by increased chlorethephon rates, and ancymidol at 0.25 mg/pot. However, increasing rates of ancymidol negated the root stimulation by chlorethephon.