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Title: The effect of heat stress on fruit-set and fruit yield of groundnut (Arachis hypogaea L.).
Author: Prasad, Pagadala Venkatat Vara.
ISNI:       0000 0001 3498 4843
Awarding Body: University of Reading
Current Institution: University of Reading
Date of Award: 1999
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Groundnuts (Arachis hypogaea L.) grown in the semi-arid tropics are commonly exposed to air and soil temperatures> 35°C. This research in controlled environments has shown that continuous exposure of plants to hot air (day/night, 38°/22°C) and/or hot soil (38°/30°C) temperatures during the reproductive .phase (from flower bud appearance until reproductive maturity) significantly reduces total dry matter production, the partitioning of dry matter to pods and seed yields. The effects of hot air and hot soil temperature were additive and without interaction. Hot air temperature had no effect on flower production but significantlyreduced the proportion of flowers setting pegs (fruit-set) and hence the number of fruits. In contrast, hot soils significantly reduced flower production, the proportion of pegs forming pods and 100 seed weight. There was no evidence that plants dependent on symbiotic N2 fixation were more susceptible to heat stress than those dependent on inorganic N. Sensitivity to short (6 d) episodes of hot air temperature (38°/22°C) was acute during the period between 6 d before until 15 d after first flowering (OAF). The magnitude of that sensitivity depended on the number of floral buds exposed to heat stress before anthesis. In the Spanish cv. ICGV 86015, daytime air temperatures ~34°C imposed for only 6 d beginning at 9 DAF, significantly reduced flower number, pollen production and viability, fruit-set and seed yield. Fruit-set was most sensitive to heat stress during the first 6 h of the daylight period (AM). Warmer nights (28° cl 22°C) had no effect on flower numbers, but significantly reduced both pollen production and viability, and hence fruit-set. There were negative quantitative relations between flower number and day temperatures between 28° and 48°C. In contrast, reductions in fruit-set were quantitatively related to AM temperature >37.3°C. Pollen production and viability were also linearly reduced when day temperature was >34°C. These data will help plant breeders to screen germplasm and identify heat-tolerant cultivars, and should also improve simulation models of groundnut crops in the semi-arid tropics.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Agronomy