Abstract:

For cultivating the herbicide-resistant rice cultivars with excellent agronomic traits, 3 derived herbicide-resistant restorer lines (Hua 84EP-1, 2 and 3) harboring EPSPS gene were mated with 5 sterile lines (Hongxiang2A, Y58S, Guangzhan63-4S, Hua1015S and Tianyuan6S). The herbicide resistance of parents and mated hybrids and the combining ability of 10 main agronomic traits of those mated hybrids, including YP (yield per plant), SSR (seed setting ratio), TGW (1000-grain weight), GP (growth period), PH (plant height), EP (effective panicles per plant), GD (grain density), NG (number of grains per panicle), NFG (number of filled grains per panicle) and PL (panicle length), were analyzed. The results showed that the herbicide resistance of 3 restorer lines was nearly complete (>96%), and it was very effective for improving the purity of rice hybrids to spray herbicide Roundup at seedling stage; the general combining ability of restorer lines and sterile lines reached significant differences in 5 traits (SSR, GP, etc.) and 7 traits (SSR, TGW, etc.) respectively; and the special combining ability of the mated hybrids only reached significant difference in GP. Among these hybrids, Tianyuan6S/Hua84EP-1, Hongxiang2A/Hua84EP-3 and Hua1015S/Hua84EP-1 had the highest yield increase compared with the control. Therefore, using herbicide-resistant restorer lines as male parent can not only improve the purity of hybrids, but also cultivate strong-heterosis combinations.

Key words: herbicide-resistance, rice, EPSPS, combining ability, heterosis