Genetic control of post-flowering osmotic adjustment and dehydration tolerance components in sorghum (Sorghum bicolor (L) Moench) under induced drought stress /
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| Other Authors: | , , |
| Format: | Thesis Book |
| Language: | English |
| Published: |
1991.
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| Subjects: | |
| Online Access: | Link to OAKTrust copy |
| Abstract: | Four sorghum parental lines, RTx430, BTx3197, RTx7000, and B35 and their F1 and reciprocals, F2 and backcross progenies were evaluated during their reproductive phases to identify physiological components underlying field post-flowering drought responses in the inbred parents and to assess the genetic basis of those components. Two greenhouse experiments were conducted under induced water stress conditions at College Station. Relative water content (RWC), water potential (ψ), osmotic potential (π) and soluble sugars were monitored bi-weekly. Agronomic evaluations were made under field conditions at College Station, Lubbock irrigated, Lubbock dryland and Chillicothe dryland. Significant differences were found among inbreds for all components at all stress levels except soluble sugars which differed only with stress levels. B35 and BTx3197 consistently maintained high RWC, ψ, π, and had the highest soluble sugars, and least % cell damage. RTx7000 had low RWC, ψ and low in soluble sugars and had higher % cell damage. Maintenance of high RWC, ψ, and high π was found to be correlated with accumulation of soluble sugars in the culm (osmotic adjustment). Parental cultivars were more resistant to heat than their hybrids and they had high accumulation of sugars. Among the hybrids, crosses made with B35 were visibly more water-stressed, but had greater mass compared to crosses with BTx3197, suggesting faster rate of water utilization, thus making them more prone to drought stress earlier than smaller plants. Depending on the parental combinations, hybrids were either higher or lower in RWC, ψ and π than any of the parents. Paired mean tests indicated significant differences between reciprocal crosses indicating cytoplasmic effects for the expression of the traits. Inheritance of high RWC, ψ, π, and heat resistance were determined to be under a multiple-locus system with dominant and recessive epistatic effects influenced by maternal effects... |
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| Item Description: | Typescript (photocopy). Vita. "Major subject: Plant Breeding." |
| Physical Description: | xvii, 153 leaves : illustrations ; 29 cm |
| Bibliography: | Includes bibliographical references. |