Genetic studies on yield, yield components and fiber properties in segregating generations of an intraspecific cotton cropss

Estimation of gene action through partioning of genetic variance was carried out, using the parents, F1, F2 and F3 populations in the cross Giza 90 x Pima S62 (24202). Results showed that the heterotic effects relative to better parent (useful heterosis) were positive and highly significant or significant for all studied characters except for First Fruiting Node (FFN), boll weight (BW), micronair value (Mic), Fiber strength (St) and Fiber elongation (Elon %), while days to first flower (DFF) recorded highly significant better parent heterosis value. Mid-parent heterosis values were highly significant and negative for days to first flower (DFF) and boll weight (BW). On the other hand, the remaining traits revealed positive and highly significant or significant heterotic effects except for First Fruiting Node (FFN), lint percentage (L %), micronair value (Mic) and Fiber elongating (Elon %) which showed insignificant heterotic effects. . High values of broad sense heritability (over 50%) were detected for first fruiting node (FFN), boll weight (BW) and Fiber elongation (Elon %). Moderate heritability estimates (between 30% and 50%) were found for seed cotton yield/plant (SCY/P), lint yield/plant (LY/P), seed index (SI), lint index (LI), micronair value (Mic), uniformity index (UI) and upper half mean length (UHM). Low broad sense heritability values (less than 30%) were obtained for days to first flower (DFF), lint percentage (L %) and Fiber strength (St). Narrow sense heritability estimates were calculated for lint index (LI), Fiber strength (St), uniformity index (UI) and upper half mean length (UHM), which exceeded 50% value. Moderate heritability estimates were observed for first fruiting node (FFN), seed cotton yield/plant (SCY/P) and lint percentage (L %). On the other hand low heritability values in narrow sense were obtained for days to first flower (DFF), boll weight (BW), lint yield/plant (LY/P), seed index (SI), micronaire value (Mic) and Fiber elongation (Elon %). It could be concluded that the selection improvement of first fruiting node (FFN), seed cotton yield (SCY/P), lint percentage (L%), seed index (SI), uniformity index (UI) and upper half mean length (UHM) traits could be achieved in early segregating generations, but the other traits need intensive selection in later generations.