Techniques of Thermo-photo Sensitive Two-line Hybrid Wheat F_1 Seed Production in Yunnan

In order to set up the techniques of thermo-photo sensitive two-line hybrid wheat seed production in Yunnan plateau,study on key technical measures concerned with purity and yield of F_1 hybrids were conducted in the F_1 seed production from 1997 to 2005 with two hybrid varieties Yunza 3(C49S-87/98YR5) and Yunza 5(K78S/01Y1-1069).Result showed that the row-ratio of male vs female had significant effect on seed yield,the optimum row-ratios of Yunza 3 and Yunza 5 were 2∶8 and 2∶6,respectively.When sterile line C49S-87 was used,the number of tiller spikes per plant should be controlled to less than 3 to guarantee the seed purity.And the leaf age,pulvinus distance and the length of young ear could be used as effective morphological indicators for predicting the flowering dates of male and female.In addition,practices from seed production with C49S-87 and K78S indicated that fertility parameters and outcrossing ability of sterile line play decisive role in determining the technicals and effectiveness of hybrid seed production.Since 2003,one set of simple,highly effective and low cost techniques for hybrid seed production based on thermo-photo sensitive genic male sterile(TPSGMS) line K78S were established,with average hybrid seed yield of 3 750 kg/hm~2(except male yield in the area) and of purity 98% in practical application of hundreds of hectares.