Correlation among Shell Percent, Cocoon Yield and Reeling Parameters of Multi × Bi Cocoons under Different Agro-Climatic Conditions of West Bengal, India

Abstract

Three new Multi <TEX>${\times}$</TEX> Bi combinations M.Con.4 <TEX>${\times}$</TEX> (SK6 <TEX>${\times}$</TEX> SK7), M.Con.4 <TEX>${\times}$</TEX> NB4D2 and Nistari <TEX>${\times}$</TEX> (SK6 <TEX>${\times}$</TEX> SK7) were studied in five seasons i.e. during the period of <TEX>$18^{th}$</TEX> June - <TEX>$12^{th}$</TEX> July, <TEX>$30^{th}$</TEX> August - <TEX>$23^{rd}$</TEX> September, <TEX>$3^{rd}$</TEX> November - <TEX>$2^{nd}$</TEX> December, <TEX>$29^{th}$</TEX> January- <TEX>$2^{nd}$</TEX> March and <TEX>$30^{th}$</TEX> March-<TEX>$25^{th}$</TEX> April with one control Nistari <TEX>${\times}$</TEX> NB4D2 considering nine reeling characteristics along with shell percent and cocoon yield per 100 disease free layings (DFLs) to establish the seasonal effect on all the parameters. Results reveal that all the characters performed well in November-December. Highest yield per 100 DFLs was recorded during November-December in all combinations showing >60 kg yield. Higher correlation of yield/100 DFLs with filament length, non-breakable filament length, denier, raw silk percent, reelability percent and recovery percent was recorded in all combinations of Multi <TEX>${\times}$</TEX> Bi considered in this study. Variability observed among four combinations indicates the effect of different temperature and humidity of different seasons on expression of different traits. The results indicate that there is significant relationship of raw silk percent with reelability percent, recovery percent and evenness. Reelability percent showed higher correlation with recovery percent. It was observed that neatness was positively correlated with evenness. The overall performance of the newly evolved combinations with regard to productivity and reeling characteristics is discussed emphasizing their utilization at commercial level.