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Studies on genetic gains in grain yield and other traits may be very useful in providing necessary information to plant breeders about the effectiveness of their breeding programs. The objective of this research was to analyze changes in grain yield, yield stability and morphological characteristics of maize hybrids released in Serbia between 1978 and 2011. Five hybrids, representatives of different breeding periods, were chosen for this study. Field trials were conducted during 2013 and 2014 at three locations in Serbia. The estimated genetic gain per breeding period was 440 kg ha(-1) which corresponds to an approximate annual linear increase in yield of 63 kg ha(-1). Changes in morphological characteristics were presented graphically, compared to the reference value and defined by the third period of breeding. Plant and ear height, kernel row number, number of kernels per row and leaf number were reduced compared to the third breeding period. Kernel depth showed higher variation through periods while in other analyzed traits, major changes in value through the periods were not found. Stability analysis distinguished the hybrids from the sixth and seventh period of breeding as the most stable, whereas the most unstable were representatives of the fifth and third period. Changes in certain morphological traits and yield stability have led to an increase in the genetic potential of the hybrids most probably through the increased tolerance to biotic and abiotic stress factors.

Agronomic field performance traits and leaf chemical characteristics of gynogenic doubled haploids (GDH) and androgenic double haploids (ADH) were compared with selfed lines of a burley tobacco cultivar to determine which type of doubled haploids was superior. Three sets of ADH and GDH lines performed similar to their selfed lines, but one set each of ADH and GDH lines had reduced yield, plant height, leaf number, stalk diameter, and leaf length in comparison to the respective selfed lines of KY 17.

In Hybrid Tea-roses relations between growth and juvenile period (J.P. = number of days from seed germination to flower bud appearance) were studied for three years. Plants showing a flower bud for the first time are significantly longer than those without a bud. In comparison with plants with long J.P.'s, plants with short J.P.'s have shorter shoots both at bud appearance and at first flowering, flower sooner, are significantly longer when measured on one date, and yield about three times more cut flowers in 6 months. It was shown that the J.P. depends on plant development and does not govern this process.

Extensive prebifurcation shooting which terminates in fruits is present in certain cultivars (e.g. Santaka) of Capsicum annuum L. Plants with such architecture setting their fruits along the periphery may therefore be expected to be suitable for mechanical harvesting. From inheritance studies (parents. F1 's and two different F2 populations) it was found that prebifurcation shooting, though a quantitative character, is controlled by relatively few genes. Few genes control main stem length and also leaf number of main stem. Correlations between the above three traits were not significant.

Fifty-five radish selections, comprising 39 named cultivars, were grown for classification based on morphological characteristics. The major characters used were the ratio of length to width of the hypocotyl, and the colour of the hypocotyl. Cultivars were further subdivided by the length of the longest leaf and the number of fully expanded leaves at harvest. The coefficient of variation is given for each cultivar. The classification identifies a total of 25 classes based on combinations of root shape and colour. These classes can then each be subdivided 25 times based on combinations of leaf length and leaf number.

This study relates the yield of two harvests of Bromus inermis Leyss. to tiller type and morphology. Tillers were classified as being nonelongated, elongated and headed. At four times during the growing season, observations were made of tiller density; individual tiller weight; leaf number, area and weight; stem length, area and weight; leaf to stem ratio; specific leaf weight; head area and weight.

Chrysanthemum morifolium seedlings and cuttings from those seedlings were grown to flowering at 17°C, short days (8 h) and two levels of irradiance (10 and 30 W m−2). The cuttings flowered more readily than the seedlings at both irradiances, Especially at 10 W m-2 many seedlings remained vegetative. The delay in flowering of the seedlings was accompanied by a higher number of leaves produced before flowering. The number of leaves produced by the seedling in excess of the number of leaves produced by the cutting from that seedling varied considerably between genotypes. The correlations between seedlings and the corresponding cuttings for days to flowering and number of leaves were low but generally significant. It is concluded that cuttings are preferred over seedlings in breeding programmes that aim at developing chrysanthemums for low light winter production.

Photoperiodic respose, as assessed by a regression technique, exhibited complete dominance averaged over the crosses of an eight parent diallel in the vernalized condition. Photoperiodic response as final leaf number for the vernalized 8-hour photoperiod diallel was closely related to photoeriodic response of the regression method. However, the diallel analyses of both sets of data showed little agreement in terms of respectieve array positions.

1. Plants of Callistephus chinensis cv. ‘Giant Comet’ were subjected to photoperiods of 8 or 16 hours. In short day (SD) a much greater number of leaves was formed than in long day (LD) before the terminal inflorescence was initiated. By transferring plants from LD to SD at weekly intervals it was established that in LD floral induction is completed about 6 weeks after sowing. 2. Inflorescence development proceeds faster in SD than in LD. Plants in continuous SD or LD flower almost simultaneously. Plants transferred from LD to SD six weeks after sowing, flower about a month earlier than those plants grown entirely in LD. 3. Gibberellic acid (GA3) did not affect inflorescence initiation in LD. In SD, however, GA3 applications reduced the number of leaves formed before the inflorescence. The maximal effect, obtained by spraying with a solution of 25 mg GA3/1 during 30 days, halved the difference in leaf number of untreated plants in LD and SD. The same effect was obtained when plants were sprayed 10, 20 or 30 times during this 30 day period. 4. Manipulation of the photoperiod allowed the development of a method to grow two generations within one year. This method, which is being used to speed up a breeding project, is briefly described.

In the phytotron of our Institute the effect was studied of different day and night temperatures on the shoot growth of first- and second-year seedlings of Limburgse Boskriek (Prunus avium L.) grown under natural daylength conditions. It was found that, after termination of growth, significant differences occurring simultaneously in shoot length and leaf number between the temperature treatments were mainly due to the effect of the day or night temperature on the duration of growth. In some cases these differences were also influenced by the effect of temperature on the rate of growth. Within the range of temperatures studied, no effect of the night temperature on the rate of growth was observed.