Ten pearl millet genotypes selected on the basis of response to supra-optimal temperature tolerance were crossed in a half-diallel mating system. The 45 hybrids produced were tested along with parents for heat tolerance and related traits at seedling stage. Field screening and laboratory screening techniques were simultaneously used for the evaluation of hybrids and their parents. Heat tolerance was measured as seedling thermotolerance index (STI) and seed to seedling thermotolerance index (SSTI) under field conditions, but membrane thermostability (MTS) in the laboratory. The hybrid H77/29-2 CVJ-2-5-3-1-3 showed highest STI value followed by H77/833-2 96AC-93. The genotype H77/833-2 96AC-93 had the highest worth for SSTI. These three indices were highly correlated among themselves. STI values were invariably high, whereas SSTI has lower values, as it also covers the effect of under soil mortality (USM). It was seen that the heat tolerance indices STI and SSTI were not showing any perceptible pooled correlation with developmental traits except germination and emergence rate. Based on our results, it could be suggested that membrane thermostability (MTS) may be used for screening large number of genotypes. Field based indices STI and SSTI may be used for evaluation of hybrids and varieties before they are released. 1. Introduction Pearl millet [Pennisetum glaucum (L.) R. Br.] is a multipurpose cereal grown for grain, stover, and green fodder. It is the most important staple crop in the semiarid and arid regions of Asia and sub-Saharan Africa. It shall continue to play a prominent role in the integrated agricultural and livestock economy of the country particularly in rainfed areas due to its drought hardiness. Pearl millet provides an excellent nutritious food because of high biological value, more protein (11.6%), fat (5%), and mineral content (2.3%). It also contains adequate amount of essential amino acids such as tryptophan, threonine, arginine, and lysine. Pearl millet is also high in lipids and calcium and low in crude fibre. Adequate crop stand establishment problems are severe constraints to get good production of pearl millet. Failure to obtain adequate plant populations is often associated with high temperatures occurring during the germination and seedling establishment period of pearl millet. The temperature is one of the key climatic factors and has profound effect on the growth and development of the pearl millet. The soil temperatures in farmers’ field in India and Africa commonly exceed 45°C and the temperatures as high as 60°C have
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