Disección fenotípica de tres caracteres asociados a la tolerancia a la sequía en trigo duro
2010
Samah, S.
The aim of this study was the phenotypic dissection of three traits related to drought tolerance in durum wheat. Plant material consisted in three mutants derived from cv. Borgia: a chlorophyll-deficient mutant (MD597), an early-senescence mutant (MD178), and a mutant with enhanced early vigor (MD483). Under field conditions water stress reduced yield by 17.5%, mainly due to a decrease in the number of spikes per plant. The chlorophyll deficiency and the early senescence traits were expressed in the mutants, although mutant MD483 did not show the expected ‘early vigor’. The lack of expression of the trait was probably consequence of the adverse environmental conditions after planting. As a result this mutant did not differ from cv. Borgia in any of the studied traits. The trait ‘early leaves senescence’ of mutant MD178 was more harmful for yield in the irrigated treatment than in the rainfed one, but this mutant did not differ from cv. Borgia in any of the studied variables. The chlorophyll-deficient mutant was the most different form Borgia. Under irrigated conditions, and mostly in the early stages, the mutant showed a delay of 1 to 2 days on its phonological development. Under field conditions its growth was poorer than that of Borgia, mostly due to a reduced growth of the stems. There were not differences with the mother variety in stomatal conductance, water potential, nor photosynthesis during grain filling. Differences in yield and yield components among both genotypes were only significant in the plants grown in the greenhouse, where water deficit was more severe than in the field. The deficiency in chlorophyll content was more damaging under terminal water stress that in less-limiting conditions, although the results suggest lower levels of photoinhibition and light saturation, and better capacity of heat dissipation in the mutant than in the mother variety
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