Studies On The Breeding And Utilization Of Early Indica Rice Cytoplasmic Male Sterile(CMS) Lines Xu 29 A

An new CMS line Xu 29 A with good quality,short growth period and strong resistance was developed,its characters and utilization were studied,the main results were as follows:1.Xu 29 A,developed from the cross and backcross of V 20A//(Digu B / Jin 23 B)F3 by Hunan Hybrid Rice Research Center,is a mew early-season indica CMS line.It was certified by the Hunan Provincial Crop Variety Appraisal Committee in March,2004. It has short growth period with its duration from seeding to heading 1～3 and 3～5 days shorter than those of 23A and V20A.The growth period of combinations combined with Xu 29A were 3 days shorter than that of 23A,and 5～7days short than that of V20A under situation of the same male parent.It was favorable to developing short or middle maturity early indica hybrid rice.Xu 29 A had good plant type with dwarf plant height of 55-60 cm,purple of sheath,shell point and stigma,9-10 effective panicles of per plant,19-20 cm of panicle length,100-110 total spikelets of per panicle,about 23%of panicle enclose,23g of 1000-grain weight,It had good grain quality with long and slender of grain shape,strong resistance to blast.2.Xu 29 A shows a stable and complete male sterility,a relatively centralized blooming period with early blooming,high rates of forenoon blooming spikelets and stigma exsertion rate reached 89%,and double stigma exsertion rate was above 55%.It was good response to GA3,and had high hybrid seed production and yielding multiplication for its characteristic of strong stigma vigour and high outcrossing seed-seting rate.Besides these,It had more amount seed in the same weght because of its lower 1000-grain weight,therefore,seed cost of production can be reduced for farmers.3.Five restorer lines were used to cross with Jin23 A and Xu29A,respectively,The practical characters,combining ability and genetic correlation of the two CMS lines and their combinations were analyzed.The results showed that the gca of Xu29A were positive value in effective panicle per plant,seed setting rate,yield of per plant,grain desity,and daily grain yield;and negative in total grain number of per panicle,filled spekelete of per panicle,1000-grain weight,growth period,panicle length,which indicated that combinations derived from Xu 29A had shorter growth period,stronger tilling,more panicle number per plant,higher seed setting rate and yiled potential.