EMPLOYMENT OF IMMATURE EMBRYO CULTURE FOR IN VITRO SELECTION OF DROUGHT TOLERANT SOMACLONES OF WHEAT

摘要

Drought, a serious threat to world agriculture, demands neo-breeding approaches. Tissue culture being a mutagenic process induces somaclonal variations, which can be manipulated for improving drought tolerance of commercial cultivars of wheat. Presentstudy was conducted to explore potential of somaclonal variation to produce drought tolerant somaclones of wheat. PEG-6000 tolerant calli induced from immature embryos of wheat cv. GA-2002 were screened and regenerated to somaclones. The somaclones wereselfed to produce R, seeds. The progeny of Rj seeds (R, generation) and their donor parent cv. GA-2002 were raised in pots and compared for drought tolerance by withholding water for 2, 4, 6, and 8 days along with control. Water stress led to reductionof relative water content (RWC), excise leaf water loss (ELWL), leaf succulence and specific leaf weight (SLW), while an increase in ABA content of both Rj somaclones and their parent cv. GA-2002. The R, somaclones showed significantly greater tendency to conserve RWC, leaf succulence and less ELWL in response to higher regimes of water stress imposed for six or eight days. Similarly, significantly higher ABA contents were accumulated by R, somaclones than parent cv. GA-2002 in response to water stressof 4, 6 and 8 days. Results from physico-chemical bases of drought tolerance indicated that R, somaclones had higher drought tolerance than their parent cv. GA-2002 and suggested possibility of in vitro selection of drought tolerant plants of wheat usingimmature embryo culture.