Papers by Shadman Namazov
E3S web of conferences, 2024
E3S web of conferences, 2023
The wide range of possibilities of using double, complex and double crossing methods in cotton ha... more The wide range of possibilities of using double, complex and double crossing methods in cotton has been studied in selection research. As a result of the use of complex hybridization, valuable traits of varieties of different genetic origin can be collected in a single genotype in a short period of time. Because in the hybrids created on the basis of complex cross-breeding, the variability of quantitative characters is manifested on a large scale, and the possibility of extensive selection appears in these hybrid populations. It is important to use various breeding methods in cotton selection, which are widely used in other agricultural crops. As a result of transgressive variation occurring in composite hybridization in cotton, the increase in the possibility of isolating recombinants, which are the source of new genetic variations, which gives the opportunity to create new varieties with a positive set of valuable economic characters in a short time, has been confirmed in the selection of other crops. In the article, it is stated that the correct selection of parental pairs and the use of composite hybridization method are important for the improvement of fiber yield and fiber length in the creation of new varieties of cotton. In particular, the effectiveness of using T-3377, T-3378, T-3379 varieties, created on the basis of composite hybridization, in achieving positive results in terms of fiber yield and fiber length was highlighted.
World Cotton Germplasm Resources, 2014
Cotton is the most important fiber crop and the seed from the plant is a rich source of high qual... more Cotton is the most important fiber crop and the seed from the plant is a rich source of high quality protein and oil. However, the use of cottonseed as a feed for animals is limited by the presence of gossypol, which is contained in glands in the seed. Gossypol occurs in two stereoenantiomers referred to as (+)and (-)-gossypol (Jaroszewski et al., 1992). Most of the toxicity of gossypol resides in the (-)-enantiomer (Wu et al., 1986). Gossypol helps protect the plant from pests. However, there is very limited information on how the level (+)and (-)-gossypol enantiomers correlates with insect and disease resistance. To understand the influence of (+)-gossypol level in seeds on insect and disease resistance we have initiated a study to examine if a correlations exists between percent (+)gossypol in the seed and resistance to pests. The objective of our research is to develop cotton breeding material with good agronomic qualities that are suited for growing in Uzbekistan, and with a hi...
World Cotton Germplasm Resources, 2014
Journal of Chromatography B, 2012
Gossypol is a toxic compound that occurs as a mixture of enantiomers in cotton plant tissues incl... more Gossypol is a toxic compound that occurs as a mixture of enantiomers in cotton plant tissues including seed and flower petals. The (-)-enantiomer is more toxic to non-ruminant animals. Efforts to breed cottonseed with a low percentage of (-)-gossypol requires determination of the (+)- to (-)-gossypol ratio in seed and flower petals. We report a method to quantitatively determine the total gossypol and percent of its enantiomers in cotton tissues using high performance capillary electrophoresis (HPCE). The method utilizes a borate buffer at pH 9.3 using a capillary with internal diameter of 50μm, effective length of 24.5cm, 15kV and cassette temperature of 15°C. This method provides high accuracy and reproducible results with a limit of detection of the individual enantiomers of less than 36ng/mL providing base line separation in less than 6min.
Cottonseed cannot be used directly as a feed for non-ruminant animals because it contains the tox... more Cottonseed cannot be used directly as a feed for non-ruminant animals because it contains the toxin gossypol. However, gossypol occurs in two forms (+)-gossypol and (-)-gossypol. Only the latter shows a high level of toxicity. The objective of our research was to develop breeding germplasm with a high percentage of (+)-gossypol in seed that will serve as a new source of plant protein that can be safely used as a feed for non-ruminant animals. To develop cottonseed that contains a high percent of (+)-gossypol, we determined the inheritance and variability of this trait in hybrids derived from U.S. accessions BC 3 S 1-47-8-1-17 and BC 3 S 1-1-6-3-15 that exhibit the high percent (+)-gossypol seed trait and Uzbek varieties S-6524, S-6530 and S-6532, and lines L-10/04, and L-16/04. In field and greenhouse studies we found an intermediate inheritance of (+)-gossypol percent in petals and seeds among F 1 hybrids and positive and negative transgresses in F 2-F 3 hybrids. The (+)-gossypol contents in flower petals were positively correlated (r=0.69-0.91) with (+)-gossypol content in seed of F 2 hybrid populations. The percent (+)-gossypol in flower petals can be used as an efficient predictor of percent (+)-gossypol in cottonseed. Low correlations were observed between percent of (+)-gossypol in seed and total gossypol in seed, and with agronomic qualities including weight of 1,000 seeds, weight of bolls, seed yield, fiber length and fiber output. The low correlation values between percent of (+)-gossypol in seed with total gossypol and the other agronomic traits indicate that the high percent (+)-gossypol seed trait is inherited independently of these other agronomic traits. This should allow the selection of progenies with a high percent of (+)-gossypol in the seeds in combination with desirable agronomic traits.
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Papers by Shadman Namazov