Quantifying pearl millet response to high temperature stress: thresholds, sensitive stages, genetic variability and relative sensitivity of pollen and pistil.
The objectives were to (1) quantify high temperature (HT) stress impacts at different growth stages (season long, booting to seed-set and booting to maturity) on various yield components; (2) identify the most sensitive stage(s) to short episodes of HT stress during reproductive development; (3) understand the genetic variations for HT stress tolerance based on cardinal temperatures for pollen germination; and (4) determine relative sensitivity of pollen and pistil to HT stress and associated tolerance or susceptible mechanisms in pearl millet. High temperature stress (≥36/26°C) imposed at different stages and durations caused decrease in number of seeds, individual seed weight and seed yield. Two periods (10-12 days and 2-0 days before anthesis) were identified as most sensitive to short episodes of stress, causing maximum decreases in pollen germination percentage and seeds numbers. HT stresses of ≥36/26°C results in floret sterility. Pistils were relatively more sensitive than pollen grains, causing decreased number of seeds and seed yield. HT stress increased the reactive oxygen species contents and decreased the activity of the antioxidant enzymes in both pollen and pistils. Under HT stress, pistils had relatively higher reactive oxygen species and lower antioxidant enzymes activity compared with pollen grains, which explains greater susceptibility of pistils.
Department of Agronomy, Throckmorton Plant Science Center, Kansas State University, Manhattan, KS, USA.|Department of Crop Physiology, Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu, India.
M
M
Djanaguiraman
Department of Agronomy, Throckmorton Plant Science Center, Kansas State University, Manhattan, KS, USA.|Kansas State University, Agricultural Research Center, Hays, KS, USA.
R
R
Perumal
Department of Agronomy, Throckmorton Plant Science Center, Kansas State University, Manhattan, KS, USA.
I A
IA
Ciampitti
International Crops Research Institute for the Semi-Arid Tropics, Patancheru, Telangana, India.
S K
SK
Gupta
Department of Agronomy, Throckmorton Plant Science Center, Kansas State University, Manhattan, KS, USA.
P V V
0000-0001-6632-3361
PVV
Prasad
D035264:Flowers / Q000235:genetics / Q000502:physiology; D014644:Genetic Variation; D006358:Hot Temperature; D031782:Pennisetum / Q000235:genetics / Q000502:physiology*; D011058:Pollen / Q000235:genetics / Q000502:physiology; D017382:Reactive Oxygen Species / Q000378:metabolism*; D012621:Seasons; D012639:Seeds / Q000235:genetics / Q000502:physiology; D013312:Stress, Physiological
D017382:Reactive Oxygen Species
High temperature stress; pearl millet; pistil; pollen; reciprocal cross; sensitive stage