RELATIONSHIPS OF SEED AND GERMINATION MEASUREMENTS WITH RESISTANCE TOSEED WEATHERING IN COTTON

Improved ability to tolerate seed deterioration associated with field weathering is needed in cotton, Gossypium hirsuttum L., genotypes to i mprove stands. The objective of this study was to determine the relati onships among selected seed physical parameters and germination variab les and their relationship with germination after simulated field weat hering. Non-deteriorated seed of eight cotton genotypes were evaluated for weight, volume, density, water imbibition rate, germination speed and germination percentage. Seed were deteriorated by treatment in ho t water (65 degrees C) for 30 min and evaluated for germination speed and germination percentage. Genotype differences were significant for all variables except germination speed of both non-deteriorated and de teriorated seed. Collinearity was indicated for seed weight and volume and for germination percentage of deteriorated seed and water imbibit ion rate. Variation in weathered germination percentage was best expla ined by two-variable models of seed weight with either germination of deteriorated seed or imbibition rate. However, the effect of seed weig ht became less important as more variables to weathered germination pe rcentage were added to the models. Resistance to seed deterioration as sociated with field weathering may be improved in cotton by selecting genotypes that have either high germinability after hot water treatmen t or a low water imbibition rate. In addition, high seed weight, volum e, and density may be effective indirect selection criteria for increa sing resistance to deterioration.z