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The 70th anniversary of the Cotton Improvement Conference (CIC) was celebrated at the 2018 annual meeting. The CIC was organized in 1948 at a meeting held in conjunction with the Southern Agricultural Workers in New Orleans, LA. The structure of the CIC was informal with the purpose of allowing state, federal, and other cotton workers to report on research, exchange ideas and facilitate research program planning. The first meeting was held in Baton Rouge, LA in 1949. Few records remain of the early years of the conference even though mimeograph proceedings were produced. In 1956, the CIC joined the Beltwide Cotton Production Conference and has continued to meet annually with this group. In 1956, the Beltwide Conferences consisted of the Cotton Disease Council, founded in 1936, Cotton Defoliation -- Physiology, established in 1942, Cotton Insect Control (1947), and CIC. Through the years members of the CIC have played key roles in the Joint Cotton Breeding Policy Committee, National Cotton Variety Test Program, and the Cotton Winter Nursery. The reporting of research, exchanging of ideas, and cooperation among public and private cotton workers has persisted throughout the 70 years of the CIC and these activities have benefitted the cotton industry. The Cotton Genetics Research Award was established in 1961 by the commercial cotton breeders to recognize scientific achievement in basic research in cotton genetics, cytogenetics and breeding. [ABSTRACT FROM AUTHOR]

Jacob Osborne (J.O.) Ware (1888-1977) was an early leader in United States (US) cotton breeding and contributed significantly to the U.S. and Arkansas cotton industries. Dr. Ware bred cotton at the University of Arkansas (UA) from 1920 until 1934, when he became the senior United States Department of Agriculture (USDA) cotton agronomist at Beltsville, MD. He returned to UA in 1950 with a joint UA and USDA appointment. During his tenure, cotton occupied up to 10% of the land area of Arkansas, but state yield never exceeded 545 lb a-1. Essentially all Arkansas cotton production was rain fed with little fertilizer added and with limited insect and disease control options available. Cotton production relied heavily on hand labor, management knowledge was limited, travel was difficult, communication was restricted, and no computers existed. In this environment, Dr. Ware made significant advances in variety development, variety testing, trait evaluation (inheritance and relationship studies), writing extensive cotton breeding reviews, and became an early leader of U.S. cotton breeding. Compared to today's program, Dr. Ware encountered similarities (geography, the cotton plant, pests, breeding objectives and procedures); disadvantages (low understandings of genetics, production practices, fiber testing, and test procedures; near absence of specialized equipment and methods to document plant releases; poor transportation; and no computer technology); and advantages (less complex traits, more state support, fewer labor and government restrictions; better public relations and less administrative demands). Dr. Ware was not the first cotton breeder at UA but was the first to establish a legacy that remains today. [ABSTRACT FROM AUTHOR]

Many cotton breeding programs in the U.S. have installed an automatic weighing system in a cotton plot picker to increase operating efficiency in recent years. However, no experimental data are available to document the reliability of such a system. The objective of this study was to evaluate the accuracy, precision, and harvesting efficiency of a two-row cotton plot picker installed with an automatic weighing system with two scales based on results from replicated field tests from 2013 to 2016. Three tests each year, each containing 32 genotypes were arranged in a randomized complete block design in two-row plots by 10 m in length. The 2013 to 2015 results showed a highly significant positive correlation in seedcotton weights between the two rows of the same plot for each genotype harvested and weighed by the two scales in the picker, indicating that the two scales are consistent and reliable. In three tests in 2016, one row of each two-row plot was harvested by the picker, and seedcotton weight was compared with another row harvested by hand. A highly significant positive correlation was detected between the two harvesting methods that had similar coefficients of variation (16.14% for hand harvest vs. 16.90% for mechanical harvest). The two-row plot picker harvested a total of 368 single-row plots (10-m long) in six hours daily, whereas hand harvest by one person averaged two plots in four hours. An average of 417 kg ha-1 was lost due to the mechanical harvest. [ABSTRACT FROM AUTHOR]

Efforts to identify and introduce single genes that could maintain or increase cotton production in water-limited production settings have resulted in extremely limited success. The primary objective of this investigation was to test whether overexpression of the tomato fructokinase gene, LeFRK1, in field-grown cotton could improve fiber yield under variable growth conditions and contrasting irrigation levels in warm semi-arid environments characteristic of the Southern High Plains. A secondary goal was to determine whether a larger field-scale experiment might be justified based upon the results of this exploratory work. Cotton overexpressing LeFRK1 was field grown in small plots for three years under irrigation, contrasting irrigation levels, or without irrigation. Increased yield was found when comparing all LeFRK1 lines relative to that of the control line, though seasonal and plant-to-plant variability limited confidence in the extension of results to production scale. We hypothesized that yield improvements resulted from a suite of responses arising from increased availability of photosynthate at the leaf to the whole-plant level to developing fruits. The results suggested that LeFRK1 overexpression might be a viable approach to improving cotton yield in warm, semi-arid environments characteristic of the southwestern U.S. However, field trials under agronomically relevant systems and at agronomically relevant scales are needed to confirm these findings. [ABSTRACT FROM AUTHOR]

The New Mexico Cotton Breeding Program was established in 1926 and has been led by five generations of breeders. The program has released 37 Acala 1517 and one short-staple Upland cotton (Gossypium hirsutum L.) cultivars and numerous germplasm lines. Two Sea-Island G. barbadense L. cultivars have been released for production in the Mesilla Valley, NM. New Mexico germplasm has contributed to the development of 45% of the commercial cotton cultivars including almost all Acala cultivars in California, and has contributed to the improvement in fiber length and strength in U.S. cottons. Many Acala 1517 cultivars are tolerant or resistant to Verticillium wilt and bacterial blight. The recent releases include three transgenic Acala 1517 cultivars, one conventional and two glandless cultivars. The current research program focuses on fiber and seed quality (glandless) to develop elite germplasm with high yields and superior fiber quality and with resistance to Verticillium and Fusarium wilt, thrips, bacterial blight, leaf spot, cotton rust, and tolerance to drought and salinity. Upland × Pima introgression and development of the hybrid seed production system based on cytoplasmic male sterility and the haploid-producing system based on semigamy are also important aspects of the program. Extensive applications of genomic tools and approaches in the program include DNA marker and population development, linkage map construction, and quantitative trait locus mapping. In recent years, reduction in funding and lack of institutional support has hampered the program in delivering solutions to challenging issues such as Fusarium wilt race 4 faced by the cotton farmer. [ABSTRACT FROM AUTHOR]

Cotton breeding research was initiated at the University of Arkansas (UA) in early 1900's. Early work focused on evaluating cultivars and on making plant selections out of established cultivars. J.O. Ware who began breeding cotton in the early 1920's studied the genetics and interrelationships of several cotton traits, and released several cultivars. In 1935, he became Senior Agronomist at the United States Department of Agriculture (USDA), Beltsville, MD, then returned to UA in 1950. Several breeders followed Ware at UA. L.M. Humphrey and Ware were responsible for a series of Rowden cultivars. From 1948 until 1986, UA maintained two cotton breeding programs, one on the main campus and the other at the Cotton Branch Station, Marianna, AR. The Marianna program, directed by C.A. Moosberg (1948-1972) and C.W. Smith (1974-1986), was responsible for the release of several Rex cultivars, two stripper cultivars, and Arkot 518. Based on the main campus, B.A. Waddle (1951-1986) continued some of Ware work, and focused on early maturity, seedling vigor, host plant resistance (including the Frego bract trait), and naked and tufted seed. J.McD. Stewart filled the position held by Waddle from 1986 until his death in 2012. His work primarily focused on germplasm exploration and introgression, and cotton biotechnology. In 1988, the two traditional breeding programs were merged into one campus-based program. The program was subsequently moved to the Northeast Research and Extension Center, Keiser, AR, in 1997. F.M. Bourland has led the program since 1988, and has been responsible for almost 100 germplasm and cultivar releases and has established methods for evaluating and selecting several cotton traits. The cotton breeding program at UA continues to develop well-adapted lines and concepts that promote profitable cotton production in Arkansas. [ABSTRACT FROM AUTHOR]

Because of the continual efforts to breed cotton for increased fiber yield, several seed/fiber compositional properties have likely shifted over the decades. Conversations with breeders, ginners, and oil processers have identified several concerns, including smaller seed size, weaker hulls, increased seed and hull fragment contamination of fiber, and reduced seed oil and protein levels--all of which directly affect the economic value of the crop. To better understand these changes, field cotton samples of current cultivars were collected from areas around Stoneville, MS; Lubbock, TX; and Las Cruces, NM. The samples were ginned and cleaned to determine seed-to-fiber ratio, seed index, and the proportions of linter, hull, and kernel tissues. Kernels were then analyzed for oil, protein, and gossypol. Results from the threeyear study (2014 through 2016) indicated that the average seed-to-fiber ratio was 1.41 ± 0.11 (range: 1.19-1.61, as is basis) and has declined compared with data sets published prior to 1950. Of the varieties included in the study, seed index averaged 9.75 ± 0.99 g (range: 8.08-11.8 g, as is basis) and also showed an overall decline compared with early published data. Seed tissue proportions have changed less, although a decrease in the percentage of linters was apparent. The average level of seed oil and protein does not appear to have changed much over the years, although oil levels were very low for a few individual cultivars. [ABSTRACT FROM AUTHOR]

Cotton breeders have focused mainly on selecting for high yield and early maturity under the impact of the boll weevil (Anthonomus grandis Boh.) in the last century. Selection for high fiber quality was once a less important objective in cotton breeding. With the transition of the U.S. cotton industry from a domestic consumer to a major exporter of raw fibers into the global market and the technology advancements in the textile industry since the 1990s, the need for high fiber quality in cotton cultivars has increased. In recent years, genetic improvement in cultivars for insect resistance, disease resistance, and abiotic stress tolerance has become important for maintaining cotton yield. Under strong competition from other major crops, increasing profit in cotton production has become an urgent task for cotton breeders and increasing economic potential in cottonseed and other economic traits can help promote profits for cotton growers. In this paper, the major research projects related to cotton breeding at the USDAARS at Stoneville, MS since the 1960s are reviewed. These research projects reflect the changing needs in cotton production during the period and focus on broadening the genetic base of Upland cotton for improving agronomic traits and fiber quality in cotton cultivars by a group of scientists with different scientific disciplines. A comprehensive review of this research can help develop strategies and identify research fields to strengthen to meet challenges in future. [ABSTRACT FROM AUTHOR]

Improving fiber quality has been an important breeding goal for cotton breeders. Better understanding of fiber development helps cotton scientists to devise a strategy for crop improvement either through marker-assisted selection or via manipulation of fiber genes. USDA-ARS Southern Regional Research Center (SRRC) in New Orleans, LA has a long history of studying postharvest fiber chemistry and physics, but research on cotton fiber development in planta began only in 1985. During the period of 1985 to 2008, cotton fiber bioscience research at SRRC was led by Barbara Triplett whose research focused on dissecting cotton fiber development at the level of gene processes and testing hypotheses about the functional roles of specific genes or cohorts of coordinately regulated genes in important fiber traits. Following stakeholders' recommendations, the cotton fiber bioscience research unit (CFBRU) was established in 2007 at SRRC. Currently, research projects at the CFBRU are focusing on 1) in-depth research to understand the basic biology of cotton fiber development, 2) genetically mapping fiber quality and yield quantitative trait loci, and 3) using the obtained information in breeding to improve cotton fiber quality. Major recent accomplishments include, but are not limited to, identification of causative genes for Ligon-lintless 1 and immature fiber mutations and identification of stable large-effect fiber quantitative trait loci and their application in practical breeding. [ABSTRACT FROM AUTHOR]

Classical plant breeding relies upon the high heritability of traits under selection. The objective of this study was to evaluate the heritability of important agronomic and morphological plant descriptors which are routinely recorded in the Beninese cotton (Gossypium spp.) breeding program. These descriptors collected through plant mapping are: plant height (HT), height of the first fruiting branch (HPBF), height of the top fruiting branch (HDBFC), position of first fruiting branch (NPBF), length of the longest vegetative branch (LBV), length of the longest fruiting branch (LBF), number of vegetative branches (NBV), number of bolls on the longest vegetative branch (NCV), and number of bolls on the longest fruiting branch (NCF). Data were collected from micro-trials conducted from 2013 to 2016, using a total of 74 accessions. Broad-sense heritability was estimated using variance components from a linear mixed model. Results reveal that heightrelated traits (HT, HPBF, HDBFC) were highly heritable (H2>0.60) and positively correlated to the seed cotton yield. NBV and NPBF also were highly heritable. These traits are considered useful descriptors. Other architectural traits (LBV and LBF) are less heritable, they were less consistently evaluated, and their utility in a classical plant breeding program is suspect. NCV and NCF are characterized by high coefficients of variation (CV) and inconsistent estimates for heritability. Other descriptors may be more useful as yield components, since seed cotton yield was not a reliable descriptor. [ABSTRACT FROM AUTHOR]

Acid delinting of cotton seed presents a personal safety and potential environmental hazard for cotton breeders. A means of delinting that does not use acid, but is effective at removing linters without adversely impacting germination is needed. A prototype mechanical cotton seed delinter was developed and built at the United States Department of Agriculture - Agricultural Research Service (USDA-ARS), Cotton Production and Processing Research Unit in Lubbock, Texas in order to optimize the mechanical process of delinting cotton seed. Testing evaluated seven drum linings, one or two roller brushes used for "scrubbing" lint from the cotton seed, and two processing times, five and ten min. The primary performance metrics evaluated were lint loss (i.e. residual lint remaining on the seed after processing) and germination. Other metrics such as visible mechanical damage of the seed and visual observations of durability and ease of clean out were also noted. Results revealed an alternating brush pattern of half nylon and half steel wire bristle brushes (42N42W) to be the best drum material using either one or two roller brushes at ten min of processing time. Lint loss values of the 42N42W material with one or two roller brushes at ten min were 0.95% and 0.88%, respectively. Germination rates for 42N42W at five and ten min were 89.3% and 88.4%, respectively. The 42N42W material appeared to be the most durable and was one of the easiest materials evaluated to clean out between samples. Based on findings in this study, a commercial unit for breeders was built by BC Supply in Lubbock, Texas. The findings of this study will be used in the development of a larger-scale model to process bulk quantities of seed during commercial production. [ABSTRACT FROM AUTHOR]

Genetic gain through cotton improvement has been best established by testing obsolete and modern cultivars in the same environments. This review is an examination of the yield and growth analysis studies performed at Stoneville, MS in the 1970s and 80s. There were four yield studies that exhibited a mean increase of approximately 7.4 kg lint ha-1 yr-1 and a range from 4.8 to 10.2 kg lint ha-1 yr-1. The lowest value was observed at a low nitrogen rate of 22 kg N ha-1. Growth analysis showed earlier and more intense flowering rates in the modern cultivars than rates seen in more obsolete cultivars. This maturity difference was supported by significant, negative correlation coefficients for the relationships between the year of cultivar release and various parameters of vegetative growth later in the season. These data indicate that there was greater vegetative mass in the obsolete cultivars at that time. The opposite was true of the reproductive parameters, which were positively related to year of cultivar release. Reproductive-to-vegetative (RVR) dry weight (DW) ratio was significantly related to year of cultivar release at 69, 96, 117 and 142 days after planting (DAP) with coefficients of 0.39*, 0.50**, 0.61** and 0.53**, respectively. Further work with advanced breeding lines and present day cultivars indicated that yield increases through partitioning from vegetative to reproductive structures were likely to continue. It is not known if such alterations have been brought forward in today's biotechnologically modified cultivars. [ABSTRACT FROM AUTHOR]

Breeding for heat tolerance is complicated by the polygenic nature of the trait and genetic engineering awaits delineation of the molecular mechanisms. To understand heat-tolerance mechanisms in cotton (Gossypum hirsutum L.), the world's most important natural fiber crop, this study compared expression of selected heat-stress response genes between heat-tolerant (VH260 and MNH456) and heat-sensitive (ST213 and ST4288) cotton genotypes. Cotton orthologs of selected Arabidopsis heat-stress response genes included two heat-stress transcription factors, three heatshock proteins, and the general stress response genes: ascorbate peroxidase and the calciumdependent stress responder, ANNAT8. The seedlings and flowering plants of each genotype were exposed to heat (38°C) for 1 to 3 hours or days, respectively, followed by RNA isolation from the seedlings and ovaries of flowering plants for gene expression analysis by real-time quantitative polymerase chain reactions. All genes, except the heat-shock protein GHSP26, were found to be induced exclusively in the heat-tolerant lines. The genotype VH260, which reportedly is tolerant to extreme heat (45°C), was found to display much higher induction of these genes than MNH456, the heat-tolerance level of which has not been thoroughly studied. Further, VH260 showed high gene induction in both seedlings and ovaries, whereas MNH456 showed lower induction levels. Strong heat tolerance in VH260 most likely is based on early induction of multiple mechanisms coordinately functioning to defend the plants against membrane damage, protein denaturation, and oxidative stress, in addition to rapid sensing of heat stress to signal the defense processes at the flowering stage towards minimizing yield losses and increasing boll retention during heat stress. [ABSTRACT FROM AUTHOR]

Cotton is an economically important crop with multiple uses as fiber, biofuel, food, and feed, and drought is one of the most limiting factors in cotton production. In this study, Gossypium hirsutum 'Acala 1517-99', G. barbadense 'PHY 76 Pima' and their cross-breeding line 'Q1735-4' were grown in a greenhouse to characterize their growth and physiological responses to four substrate volumetric water contents (VWC) of 15, 25, 35, and 45%. An automated irrigation system consisting of soil moisture sensors, datalogger, and a relay controller was used. The results from two tests consistently showed that as VWC decreased, leaf area, stem diameter, and total dry weight (DW) decreased linearly for PHY 76 Pima and Q1735-4, but quadratically for Acala 1517-99. However, the reduction in the growth parameters varied among genotypes. As VWC was decreased from 45% to 25%, Acala 1517-99, PHY 76 Pima, and Q1735-4 exhibited reduction in height by 39.2, 32.5, and 23.7%; in leaf area by 70.9, 65.8, and 34.7%; in stem diameter by 33.4, 28.1, and 22.1%; and in total DW by 59.2, 55.6, and 15.1%, respectively. The interspecific cross-breeding line consistently displayed better drought tolerance than its parents. When VWC was further decreased to 15%, the interspecific cross-breeding line still had the lowest reduction in reproductive growth as measured by the total dry fruit weight; but its vegetative growth parameters such as plant height, leaf area, stem diameter, and total DW were similar to Acala 1517-99 and lower than PHY 76 Pima. [ABSTRACT FROM AUTHOR]

In the U.S., Ted Wallace coordinates a Regional Breeders Testing Network (RBTN) for cotton that is sponsored by Cotton Incorporated. The objective of this program is to provide testing sites for public breeders and geneticists across a regional basis. This study looked at various statistical aspects of field testing with emphasis on lint yield. Ten years of data (107 environments) were examined. The objectives were to: 1) determine any relationship between error variance and mean lint yield, 2) establish a procedure for rejecting less precise data, and 3) discern the most optimum testing sites in the program. To achieve the first objective the natural log of error variances were regressed on the natural log of mean environmental lint yields and tested for significance. The "b" value of 0.85 was significant indicating that the error variance increased with increasing yield levels. Using a procedure previously published on rejecting less precise data, the second objective was met. Five of the 107 environments were deemed imprecise and should not have been included in across-location tables. A genotypic index regression method was followed to ascertain the most desirable test sites in the program. Twelve of 23 test sites did an acceptable job of discriminating the entries. Thus, by eliminating nearly half of the test sites more reliable data can be produced, less seed would be required, and more efficient use of resources would be achieved. Sites with less than desirable tests might contribute by collecting data on disease tolerance, morphological traits, or insect resistance, etc. and thus might still be valuable in the cotton RBTN. [ABSTRACT FROM AUTHOR]

Trends in fiber quality of United States (U.S.) Upland cotton (Gossypium hirsutum L.) recently have been positive for the three major traits of length, strength, and micronaire. From 1980 to 2010, micronaire trended upward, but it was not highly significant; emphasis on lint yield tends to result in higher micronaire fibers. Fiber strength continues to improve despite a respite in the late 1990s when transgenic cultivars first came on the market. Much of this improvement in fiber strength can be traced back to the New Mexico State University breeding program and its impact on the cultivar Deltapine 90 which is found in many of the improved cultivars. There was one case of possible transgressive segregation for fiber strength in 2006. Fiber length trended upwards until 1997, and then declined until 2006 when it began another period of improvement that currently continues in the U.S. cotton crop. Much of the improvement in fiber length in recent years can be attributed to the introduction of Australian breeding materials into FiberMax and Deltapine cultivars. Pedigree analyses only reveals that Deltapine 90 is in the background of this genetic material, thus much of the improvement in fiber quality over these years can be traced to material developed at New Mexico State University. [ABSTRACT FROM AUTHOR]

Four hundred fifty-five new microsatellite, also known as simple sequence repeat (SSR) marker loci, were added to the previously published 2072-locus genetic map that was constructed using 186 recombinant inbred lines (RILs) from an interspecific cross between Gossypium hirsutum TM-1 and G. barbadense 3-79. The augmented high-density map contained 2527 loci (2280 SSRs and 247 single nucleotide polymorphisms) and covered 3430 centiMorgans (cM) with an average marker locus interval of 1.36 cM. An addition of 455 new marker loci (a net increase 21.96%) resulted in only 50 cM or 1.48% net increase of total genetic distance, but reduced the number of large gaps (> 10 cM) from 21 to 14. Approximately 400 pairs of duplicate SSR loci were present in this augmented map. Most duplicate loci were mapped between homeologous chromosomes. Duplicate loci within a chromosome were observed in at least nine chromosomes. The telomeric regions are hot spots for intrachromosomal locus duplication. This augmented map is a saturated genetic map of tetraploid cotton genome whose total genetic distance is estimated at approximately 3500 cM. [ABSTRACT FROM AUTHOR]