Analyzing Quantitative Trait Loci for Fiber Quality and Yield-Related Traits From a Recombinant Inbred Line Population With Gossypium hirsutum Race palmeri as One Parent

Fiber quality and yield-related traits are important agronomic traits in cotton breeding. To detect the genetic basis of fiber quality and yield related traits, a recombinant inbred line (RIL) population consisting of 182 lines was established from a cross between Gossypium hirsutum cultivar CCRI35 and G. hirsutum race palmeri accession TX-832. The RIL population was deeply genotyped using SLAF-seq and was phenotyped in six environments. A high-density genetic linkage map with 15,765 SNP markers and 153 SSR markers was constructed, with an average distance of 0.30 cM between adjacent markers. A total of 210 fiber quality quantitative trait loci (QTLs) and 73 yield-related QTLs were identified. Of the detected QTLs, 62 fiber quality QTLs and 10 yield-related QTLs were stable across multiple environments. Twelve and twenty QTL clusters were detected on the At and Dt subgenome, respectively. Twenty-three major QTL clusters were further validated through associated analysis and five candidate genes of four stable fiber quality QTLs were identified. This study revealed elite loci influencing fiber quality and yield and significant phenotypic selection regions during G. hirsutum domestication, and set a stage for future utilization of molecular marker assisted breeding in cotton breeding programs.

Cotton Byproduct Use in Southeastern Beef Cattle Diets: Quality, Intake, and Changes in Feed Characteristics

Cotton is grown on over 4.5 million hectares in the southeastern U.S. annually, and byproducts of cotton production are utilized as feedstuffs in beef systems. Cotton breeding efforts and variety recommendations for crop production represent potential changes in cotton seed size, density, and quality, which may influence whole cottonseed feed quality characteristics. Also, cotton breeding to reduce gossypol concentration without compromising yield may improve value in ruminant diets. A recent feed intake trial demonstrated greater consumption of ultra-low gossypol seed compared with seed derived from a more widely planted cotton variety (0.072% vs 0.53% free gossypol, respectively) in growing steers (1.9 and 1.1 kg/hd/d, respectively). Historically, cottonseed is limited in bull diets due to the associated of decreased fertility in males due to gossypol. However, a recent study found that feeding up to 3.2 kg/hd/d over a 60-d period to developing beef bulls did not affect sperm quality. Heat damage commonly occurs in cottonseed during storage after the ginning process, but the feed value of heat damaged cottonseed is unknown. A recent study indicated that in situ dry matter (52.2 vs 69.2%) and N (78.1 vs 91.6%) disappearance decreased for heat damaged compared to normal cottonseed, respectively. Cotton gin trash remains a prevalent byproduct with traditionally limited use. Some gins have equipment for baling gin trash in 180-to-270 kg modules, which allow ease of access and transport of gin trash waste for cow-calf producers. Similar to gin trash, grazing cotton crop residue after harvest can decrease the amount of hay fed during the winter. A recent 3-yr study indicated a 2.5 hd/ha stocking rate of mature, non-lactating cows over a 30-d period decreased hay consumption by 65 %. By understanding the feed characteristics and management needed to utilize cotton byproducts, cattle operations can decrease feed cost while maintaining animal performance.

Revamping of Cotton Breeding Programs for Efficient Use of Genetic Resources under Changing Climate

Empirical cotton breeding was based upon the concept of selecting single and best high-yielding progeny from the segregating populations to develop a cultivar. It helped in releasing of high yielding varieties with superior fibre quality through conventional breeding. Though the production of cotton has been increased manifold in the last decades, but it has also seen enormous ebb and flow of yield uncertainties during the past several years. Therefore, the development of climatic resilient cotton ideotypes through the introduction of wild alleles and using contemporary genetic markers have become inevitable. Emerging genome engineering technologies such as CRISPR/Cas9 system can also potentially exploited to edit the disease susceptible and negative regulators of yield related genes in cotton. In the present review we concentrate on accomplishments and forthcoming of plant breeding and biotechnology to facelift the cotton breeding programs.

STUDY OF MUTANT BREAKER VARIETIES ACCORDING TO THE BASIC ECONOMIC-VALUABLE SIGNS UNDER THE CONDITIONS OF KARAKALPAKSTAN

The mutant varieties M KK-3523 and M KK-3560 turned out to be relatively large-box varieties. These varieties exceeded the standard from +0.1 to +0.3 grams. In the non-irradiated variant, the large-box variety was KK-3547. According to frozen crop from the irradiated variant, the mutant variety M KK-3523 was a relatively high-yielding variety when it had an excess of yield against the standard by 10.3%. In non-irradiated grades KK-3536, KK-3548 and KK-3530 for frozen harvest had an excess against the standard from 5.0 to 6.8%. KEYWORDS: Cotton breeding induced mutagenesis, mutant, radiation dose, mutation, variety, hybrids, cell, yield, precocity, fiber yield, fiber length.

High-density linkage map construction and QTL analyses for fiber quality, yield and morphological traits using CottonSNP63K array in upland cotton (Gossypium hirsutum L.)

Background Improving fiber quality and yield are the primary research objectives in cotton breeding for enhancing the economic viability and sustainability of Upland cotton production. Identifying the quantitative trait loci (QTL) for fiber quality and yield traits using the high-density SNP-based genetic maps allows for bridging genomics with cotton breeding through marker assisted and genomic selection. In this study, a recombinant inbred line (RIL) population, derived from cross between two parental accessions, which represent broad allele diversity in Upland cotton, was used to construct high-density SNP-based linkage maps and to map the QTLs controlling important cotton traits. Results Molecular genetic mapping using RIL population produced a genetic map of 3129 SNPs, mapped at a density of 1.41 cM. Genetic maps of the individual chromosomes showed good collinearity with the sequence based physical map. A total of 106 QTLs were identified which included 59 QTLs for six fiber quality traits, 38 QTLs for four yield traits and 9 QTLs for two morphological traits. Sub-genome wide, 57 QTLs were mapped in A sub-genome and 49 were mapped in D sub-genome. More than 75% of the QTLs with favorable alleles were contributed by the parental accession NC05AZ06. Forty-six mapped QTLs each explained more than 10% of the phenotypic variation. Further, we identified 21 QTL clusters where 12 QTL clusters were mapped in the A sub-genome and 9 were mapped in the D sub-genome. Candidate gene analyses of the 11 stable QTL harboring genomic regions identified 19 putative genes which had functional role in cotton fiber development. Conclusion We constructed a high-density genetic map of SNPs in Upland cotton. Collinearity between genetic and physical maps indicated no major structural changes in the genetic mapping populations. Most traits showed high broad-sense heritability. One hundred and six QTLs were identified for the fiber quality, yield and morphological traits. Majority of the QTLs with favorable alleles were contributed by improved parental accession. More than 70% of the mapped QTLs shared the similar map position with previously reported QTLs which suggest the genetic relatedness of Upland cotton germplasm. Identification of QTL clusters could explain the correlation among some fiber quality traits in cotton. Stable and major QTLs and QTL clusters of traits identified in the current study could be the targets for map-based cloning and marker assisted selection (MAS) in cotton breeding. The genomic region on D12 containing the major stable QTLs for micronaire, fiber strength and lint percentage could be potential targets for MAS and gene cloning of fiber quality traits in cotton.