INHERITANCE OF RESISTANCE TO SEED DETERIORATION IN COTTON

Deterioration of cotton, Gossypium hirsutum L., seed can adversely aff ect stands, seedling vigor, and subsequent performance of plants, but deterioration can be lessened by improved genetic resistance. This stu dy was conducted to evaluate the relationship of physical and germinat ion characteristics of cotton seed and to determine the inheritance of resistance to seed deterioration. Physical (weight, volume, density, and imbibition rate) and germination (germination of non-deteriorated seed and deteriorated seed) characteristics were determined for eight cotton genotypes. In addition, imbibition rate and the germination cha racteristics were deter the parents for germination of deteriorated se ed and imbibition rate were significantly, highly correlated (r = - 0. 97) and intrinsically related. Resistance to seed deterioration tended to increase as seed weight and volume decreased. Significant genetic effects were found for imbibition rate and germination of both non-det eriorated and deteriorated seed. However, general combining ability (G CA) accounted for only 21% of the variation in crosses sums of squares for germination of non-deteriorated seed. In contrast, GCA accounted for 90% of the variation for germination of deteriorated seed and imbi bition rate. A breeding approach involving selection of early generati on seed for ability to survive hot water treatment, then evaluating la ter generations for imbibition rate is suggested as a means to improve resistance to seed deterioration in cotton.