School of Agriculture and Biotechnology

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Subject: search.filters.subject.Drought tolerance

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    Evaluation of drought tolerance in mutant Kenyan bread wheat (Triticum aestivum L.) using in vitro techniques
    (INNSPUB, 2016-08-31) Githinji, Gerald Gikonyo; Kinyua, Miriam; Kiplagat, Oliver; Birithia, Rael
    Wheat (Triticum aestivum L) is widely cultivated as a small-grain cereal. In Kenya, it is ranked second after maize in its contribution towards food security. Biotic stress conditions such as drought cause extensive losses to agricultural production worldwide. In Kenya, arid and semiarid lands represent 83% of total land area, which experience frequent crop failure due to drought stress. Developing drought-tolerant wheat genotypes has been the focus of many wheat improvement programs. Few drought tolerant varieties are available for commercial production in Kenya. Hence, there is need to develop more drought tolerant wheat varieties. The objective of this study was to screen for drought resistance in two mutant wheat lines in vitro using Polyethylene Glycol (PEG). Four wheat germplasm were tested for drought tolerance using -3.0, -9.0 and -15.0 PEG-6000 concentrations and the data was recorded on various seedling parameters including root length, shoot length and root length /shoot length ratio. The experiment was carried out in three replicates using completely randomized design. Data was subjected to analysis of variance (ANOVA) using GENSTAT 12th edition. Correlation was done by Pearson Correlation Coefficients to determine significant associations among the different variables. Results indicated that there was a significant difference (p=0.05) between Mutant 1 and Mutant 2 having longer roots, shoots and a root to shoot ratio compared to Chozi and Duma in the different PEG concentrations used. Hence, the two mutant lines are possible candidates for varieties that can be grown in ASALs regions in Kenya.
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    Genetic mapping and identification of quantitative trait loci for yield and drought tolerance in tea
    (2015) Kamunya, S.M.; Kireger, E.K.; Wachira, F.N.; Sharma, R.S.; Korir, R.; Maritim, T; Kiplang’at, J.; Sharma, V.; Chalo, R.; Ahuja, P.S.
    Accelerated breeding and selection of improved tea (Camellia sinensis (L.) O. Kuntze) cultivars requires sound knowledge and understanding of genetics associated with desirable attributes.Quantitative trait loci (QTL) mapping for yield and drought tolerance in tea was performed using 42 F1 clonal progeny derived from a cross between tea cultivars TRFCA SFS150 and AHP S15/10 that had been established at two distinct tea growing regions in Kenya. The 100 informative markers identified in the cross that exhibited 1:1 segregation ratio were used to construct a linkage map of tea. The map consisted of 30 (19 maternal and 11 paternal) linkage groups that spanned 1411.5 cM with mean interval of 14.7 cM between loci. QTL analysis was carried out for yield and drought tolerance produced nine putative yieldQTLs and 13QTLs for drought tolerance. None of theQTLs was congruently detected in the two sites owing to G x E interactions. Markers OPT-18- 2500 and OPO-02-900 had pleiotropic effects in that they were significantly associated with yield at Timbilil (YLD-T; P = 0.007) and drought tolerance at Kangaita (DT-K; P = 0.003). The implications of the current study with respect to mapping population, G x E and marker-assisted selection are discussed.
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