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Accueil du site → Doctorat → États-Unis → 1982 → SOME PHYSIOLOGICAL ASPECTS OF DROUGHT RESISTANCE IN WINTER WHEAT (TRITICUM AESTIVUM L. EM THELL

Oklahoma State University (1982)

SOME PHYSIOLOGICAL ASPECTS OF DROUGHT RESISTANCE IN WINTER WHEAT (TRITICUM AESTIVUM L. EM THELL

OSMANZAI, MAHMOOD

Titre : SOME PHYSIOLOGICAL ASPECTS OF DROUGHT RESISTANCE IN WINTER WHEAT (TRITICUM AESTIVUM L. EM THELL)

Auteur : OSMANZAI, MAHMOOD

Université de soutenance : Oklahoma State University

Grade : Doctor of Philosophy (PhD) 1982

Résumé
The objectives of the research were to study the influence of drought conditions on the photosynthesis (CER) of different wheat genotypes ; to determine the relative importance and relationship between drought resistance and selected plant characters ; to determine if the parents with optimum CER and stomatal diffusive resistance (Rs) can be identified through the physiological studies. The genetic importance of the desirable traits were estimated. The study was conducted under controlled conditions in the growth chamber and artificial drought stress was induced at the heading stage. Another study was carried out under field conditions on a cross of winter wheat parents and progenies. The physiological traits that have been evaluated in this research are carbon dioxide exchange rate (CER), (Rs), biological yield, agronomic yield, yield components, harvest index, leaf area, leaf length, leaf width, leaf segment area and some other plant characters. Findings and Conclusions. The data show a significant difference in total dry matter, grain yield, CER, Rs among three levels of watering. The drought tolerant cultivars had significantly higher CER and higher but not significant Rs. The regulation of gas exchange between the plant and atmosphere is an important physiological trait in relation to water use efficiency. The drought susceptible cultivar had the lowest stability for CER. A significant positive correlation between CER and total dry matter production was obtained. Broad-sense heritability of Rs was estimated (0.55) and CER (0.30). The relationship between leaf area and L x W was linear. L x W was found as an important variable in prediction of leaf area. A factor (K) 0.97 was found to be significant in determination of leaf segment area by only measuring leaf width in the equation A = K(L x W) using a standard leaf length. This indicates that a considerable saving of time with little loss of predictability could be possible by measuring only leaf segment width. The results suggest improving water use efficiency of wheat through incorporation of higher CER and favorable stomatal behavior.

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