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Title:	Evaluation of advanced rice breeding lines with and without drought tolerance QTLS in Malaysia
Authors:	Nurul Shamimi Abdul Ghani (P54309)
Supervisor:	Wickneswari Ratnam, Prof. Dr
Keywords:	Quantitative genetics
Issue Date:	17-Apr-2014
Description:	Drought is considered to be one of the major environmental factors limiting crop growth and yield in rice (Oryza sativa). This study aims to evaluate pre and post-harvest traits of advanced breeding lines with and without drought tolerant Quantitative Trait Loci (QTLs), i.e., DTY3.1, DTY2.2 and DTY12.1 under lowland and upland field conditions. The experiments were conducted at the Malaysian Agricultural Research and Development Institute in Seberang Perai, Penang. A total of 78 breeding lines with and without drought tolerance QTLs (DTY2.2 and DTY3.1) were evaluated in lowland conditions. Out of 78 breeding lines, 40 lines were from QTL DTY2.2 group and 38 lines were from DTY3.1 group. Among these 40 breeding lines from QTL DTY2.2, 20 were carrying drought tolerance QTLs and another 20 lines were without drought tolerance QTLs. Among 38 lines from QTL DTY3.1, 19 were carrying drought tolerance QTL and another 19 lines without QTL. Nineteen lines carrying QTLs and the other 19 lines without QTLs of DTY12.1 group were planted in upland field conditions. Moderate water stress resulted significant effect (p<0.05) on plant height, leaf length and width, panicle length, reproductive tiller and other evaluated traits except for days to flowering for DTY2.2 lines. Among DTY3.1 lines, phenotypic variation was observed for plant height, length and width of leaf, panicle and culm length, number of reproductive tiller and days to flowering. Drought stress affected significantly on harvest index of DTY3.1 lines. Several breeding lines carrying QTL DTY2.2 (IR83641-303-B-B, IR83641-76-B-B and IR83641-74-B-B) and lines carrying QTL DTY3.1 (IR81896-B-B-153, IR81896-B-B-181, IR81896-B-B-195 and IR81896-B-B-228) were selected for inclusion in varietal development program under water limited environment. In addition, correlation analysis indicated that, to harness high yield under drought stress, breeders should give selection pressure on panicle length, reproductive tiller per plant and biomass. Upland trial for DTY12.1 lines explored that water stress affected on the leaf rolling and leaf drying. Lines IR84984-83-15-442-B-B, IR84984-21-19-448-B-B and IR84984-83-15-863-B-B that carrying drought tolerance QTL were selected on the basis of low leaf rolling and leaf drying scores and drought stress had no effect on these lines. This study showed that plant height, number of reproductive tiller, panicle length, leaf rolling, leaf drying and harvest index should be considered for improvement of drought tolerant ri4r4ce variety by simple selection technique. The presence of QTLs for drought tolerance is useful for our understanding of the relationship between traits and yield. Thus, it will also contribute to yield improvement for both lowland and upland rice.,Master/Sarjana
Pages:	97
Call Number:	SB191.R5N846 2014 tesis
Publisher:	UKM, Bangi
Appears in Collections:	Faculty of Science and Technology / Fakulti Sains dan Teknologi

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