Evaluation of Six Foreign Cotton Cultivars Seed Cotton Yield and its Components, Earliness and Fiber quality in Golestan Province

Cultivars are the most important factor in achieving optimum quantity and quality of produce, and cotton is one of the most important industrial crops. The aims of introducing new cotton varieties are to increase yield, earliness and resistance to biotic and abiotic stress factors. Despite the improvement and introduction of many new cotton varieties in Iran in recent years, new foreign cotton varieties have also been registered, introduced and marketed in Iran for the first time. Therefore, the cultivation of new foreign cotton varieties that are early maturing, high yielding and have good fiber quality is part of the Ministry of Agriculture's development plan for cotton cultivation. This study was conducted to evaluate and compare the cotton seed yield and its components as well as some fiber quality characteristics of new cotton varieties grown in Golestan province in Anbar Olum region in order to introduce and market these varieties.

 Value of Cultivation and Use (VCU) of six new Turkish cotton varieties, including Carisma, Lydia, PG2018, BA440, Flash and Edesa, compared to Latif and Sahel varieties as control in Fars (Darab) province, evaluated in 2016 and 2017 by determining cotton seed yield and its components (number of bolls per plant and weight of a boll), earliness and fiber quality, including fiber percentage, length, fitness, flexibility, firmness, uniformity, yellowing and brightness, and verticellium wilt tolerance.

Combined analysis of variance over time showed that seed cotton yield, ginning performance, length, fineness, strength, uniformity, and fiber yellowing were significantly different among years of the experiment. In addition, the tested varieties differed significantly in terms of cotton seed yield, boll weight, ginning performance, fibre length, fineness and strength, and the interaction effect of variety x year was significant for fibre elasticity and reflectance. The new foreign variety PG2018 was the earliest maturing variety with a duration of 96.25 days from planting to full boll opening in the first year. The fineness, strength and uniformity of the fibres in the second year were higher than in the first year. The new foreign variety PG2018 had the highest grain yield, and this variety had the lowest fibre length. The fibres of the new foreign varieties Lydia and BA440 had the highest strength. The new foreign variety PG2018 had the highest cotton seed yield in the first year (3705.3 kg/ha). The fibres of the new foreign variety Edesa had the highest elasticity in the first year. The new foreign variety Lydia had the highest fibre reflectance in the first year. In addition, the new foreign varieties BA440 and Lydia were the most tolerant varieties to Verticillium wilt.

Based on the results of this study, among the six new foreign cotton varieties evaluated, the new foreign varieties BA440 and Lydia are recommended as new varieties for cultivation in Golestan province, considering the cotton seed yield and earliness of the new foreign variety PG2018, as well as ginning performance and tolerance to Verticillium wilt. In addition, these varieties should be prioritised as new varieties for cultivation in Golestan province.