PHENOTYPIC VARIABILITY OF ECONOMIC PERFORMANCE IN PLANTS OF COTTON VARIETIES

The article reveals the results of analysis in order to select primary forms for genetic-selection research to study the high and stable phenotypic potential of economic indicators of mediumfiber cotton varieties, such as cotton weight, fiber yield and length properties per unit. According to the results of the experiment, the phenotypic potential of UzFA-713 and Kelajak varieties was higher than UzFA-703, UzFA-705, UzFA-707 and UzFA-710 varieties. According to the fiber yield indicator, UzFA-705 and UzFA-710 varieties have a higher phenotypic potential than UzFA-703, UzFA-707, UzFA-713 and Kelajak varieties. UzFA-713 and Kelajak varieties can be recommended for use as a primary source on the weight of cotton in one stem and UzFA-705 and UzFA-710 varieties for fiber yield in genetic selection studies.


INTRODUCTION
It is important to select the parent forms based on of differentiating cotton varieties and thoroughly studying their characteristics, knowing exactly how they differ from each other, while maintaining the economic characteristics over the years.
The study of the phenotypic stability of genotype-enriched breeding stock in several generations of plants allows to obtain complete information about the important economic performance of these traits.
In the interpreted literature [1-6] the importance of phenotype indicators of important economic characteristics of cotton varieties and hybrids is given.
The aim of the study was to select parental forms of cotton varieties based on the study of high potential and stability in plant phenotype for three years of indicators such as cotton weight, fiber yield and fiber length in one stalk.

MATERIALS AND METHODS
In the three-generation plants of medium-fiber cotton UzFA-703, UzFA-707, UzFA-710, UzFA-713 andKelajak in 2017-2019, economic indicators of cotton varieties such as cotton weight, fiber yield and fiber length per unit were studied. The indicators of plant height, productivity, and the ball weight in cotton genotypes statistical analysis was performed using the Fisher [7] method (P <0.05 and P <0.01).

RESULTS AND DISCUSSION
In 2017, the weight of cotton in one boll was the highest in UzFA-713 and Kelajak varieties compared to other samples, the highest in UzFA-705 and UzFA-703 varieties in terms of variability, and the lowest for Kelajak variety.
In terms of fiber yield, the highest rates were observed in varieties UzFA-710 and UzFA-705, the lowest in varieties UzFA-713. It was observed that the scale of variability is higher in UzFA-713 and UzFA-707 than in other samples.
The highest values of fiber length were identified in the varieties UzFA-703, UzFA-713 and UzFA-705, and in other forms reflected a similar appearance.
The scale of population variability was higher in Kelajak variety for this category than in other forms. The highest fiber yield was observed in UzFA-710 and UzFA-705 varieties, and the scale of population variability on this trait was phenotypically expressed in UzFA-707 and Kelajak varieties.
In terms of fiber length, UzFA-703 and UzFA-705 were the lowest, with almost the same data in all other samples. The scale of variability was higher in Kelajak and UzFA-705 varieties than in other samples. In 2019, the weight of cotton in one boll is the same as in 2018, with the highest in the Kelajak variety and the lowest in the UzFA-710 variety, while in other forms it was close to each other. The scale of variability was higher in UzFA-703 and UzFA-710 compared to other hybrid varieties, and it was the lowest in Kelajak variety.
The highest fiber yield was observed in varieties UzFA-710 and UzFA-703, and the scale of variability of the population on this trait was found to be higher in varieties UzFA-705 and UzFA-707 than other samples.
The scale of variability was higher in Kelajak, UzFA-710 and UzFA-703 varieties than in other samples. The variability of the indicators was observed in the UzFA-705 variety in terms of cotton weight per unit, in the UzFA-707 variety in terms of fiber yield and in the Kelajak variety in terms of fiber length qualities compared to other items.