Screening of Drought Tolerant Agronomic Trait Indices of Colored Cotton Varieties (Lines) in Gansu Province

Available drought-tolerant indicators that help to screen drought-tolerant parents are significant for breeders to develop new varieties in the water deficient regions.In the paper, the water deficient trials were performed with randomized block design with three treatments.The agronomic traits and drought-tolerant indicators of eight colored cotton varieties (lines) were investigated in 2010-2011.The results showed that the seed cotton yield reduced, and plant height, leaf number at flowering-bolling stage, boll number per plant, number of fruiting branch, number of fruit nodes, single boll weight, harvest index, stem diameter, seed index, and fiber length also decreased under drought stresses.There were significantly positive correlation among drought resistance index, plant height, number of fruit nodes, boll number per plant, leaf number at flowering-bolling stage, single boll weight, harvest index, stem diameter, and number of fruiting branch.The principal component and the multiple stepwise regression analyses showed that the boll number per plant, single boll weight, and the leaf number at flowering-bolling stage could be regarded as the simple and intuitive identification indexes of drought resistance in colored cotton, and number of fruiting branch, fiber length, plant height, number of fruit nodes, boll weight, and seed index could be used as indicators for determining or influencing colored cotton drought resistance.