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Genetic Studies On Drought Resistance By Selection Introgression Lines In Rice

Posted on:2012-10-16Degree:MasterType:Thesis
Country:ChinaCandidate:H GaoFull Text:PDF
GTID:2213330344952544Subject:Crop Genetics and Breeding
Abstract/Summary:PDF Full Text Request
Drought is the major limiting factors in the rice production. Discovery and application of drought-resistance (DR) QTLs from germplasm is an effective way to improve drought resistance of rice varities. A strategy based on the development of multi-parental introgression lines, together with target trait screening and molecular marker survey, was used to map QTLs and develop back-cross deried breeding lines. Drought resistance QTLs from different donors could be pyramided by making cross among introgression lines.In this study, a maintainer line with high grain quality and strong drought resistance (Huhan 1B, HB) and a wide-compatible CMS restorer line (Zhong 413) were used as recurrent parents to develop introgression lines, respectively. The agronomical and yield performance in drought condition of all ILs were repeatedly evaluated. ILs were genotyped with molecular markers for QTL analysis. The main results of the expriments were summarized as follows:1. The BC2F2 population was developed between HB(recurrent parent) and Wuzuihonggu (donor parent). The yield characters of 116 ILs were evaluated under irrigation and drought conditions in Shanghai. There were large variations in all traits related to yield. Correlation analysis showed that effective panicles per plant and number of spikelets per panicle formation a larger contribution to yield, but the spikelet number per panicle was the most susceptible trait to drought stress. Based on drought-coefficient (DC), two groups of ILs were selected, i.e.20 drought-resistance lines (DC>0.86, Group I) and 20 drought-sensitive lines (DC<0.50 Groupâ…¡). All yield components, other than seed setting rate and hundred grain weight, had significant difference between two groups. The 116 ILs were genotyped with 97 well distributed polymorphic SSR markers. A total of 24 and 20 QTLs were identified in irrigation and drought conditions by One-way ANVOA (P<0.001) on chromosomes except chromosome 9 and 12. A total of 30 DR-QTLs were identified through x2 test (P<0.0001) based on the introgression frequency between Group I and Groupâ…¡. Nine loci of which were identified in One-way ANVOA and% test.2. ILs populations were developed using Zhong 413 as the recurrent parent, and C418, Yuexiangzhan, MR167, etc. as donors. Introgression-line pyramiding-derived-lines (PDLs) were developed by inter-crossing among introgression lines selected under drought condition. Four lines (KH168, KH172, KH268 and KH415) showed strong drought tolerance at vegetative stage in both field and PVC-tube experiments. Both KH168 and KH172 can maintain high relative water content under water deficit in comparison with the typical upland variety IRAT109 (CK1) and the recurrent parent Zhong 413 (CK2). While both control varieties had severe leaf rolling and desiccation, two PDLs maitained better leaf growing status and had significantly less leaf rolling and desiccation.The KH268 and KH415 have better yield performance after drought treatment. The four lines were genotyped using 351,351,308 and 299 polymorphic SSR markers, respectively. The result showed that KH168 carried 81 introgression segments, KH172 carried 77 segments, KH268 carried 56 segments and KH415 carried 64 segments, distributing on 12 chromosomes. In most cases, introgression components on each chromosome came from both donor parents.
Keywords/Search Tags:rice (Oryza sativa L.), recurrent parent, backcross, introgression lines, QTL, pyramiding, drought resistance
PDF Full Text Request
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