High temperature during reproduction is a major factor limiting the yield of chickpea (Cicer arietinum L.). Observations in the field from late season experiments (Feb-2 May) and various high temperature regimes generated in controlled environments showed clear genetic variation in male reproductive tissue (anther and pollen), its function (pollen germination and tube growth) and pod set. Greater pod setting ability of heat tolerant genotypes (ICC 1205 and ICC 15614) compared to heat sensitive genotypes (ICC 4567 and ICC 10685) was observed in both the field and controlled conditions. Both anthers and pollen showed more structural abnormalities under stress such as changes in anther locule number, anther epidermis wall thickening and pollen sterility, rather than function (e.g. in vivo pollen tube growth). The critical temperature for pod set was ≥ 37˚C in heat tolerant genotypes (ICC 1205 and ICC 15614) and ≥ 33˚C for heat sensitive genotypes (ICC 4567 and ICC 10685). Overall, pod set showed greater sensitivity in the controlled environments where a 67% reduction was observed at ≥ 34/19˚C compared to the control (27/16˚C). In the field, a pod set reduction of more than 50% occurred at high ambient day temperature (36˚C) and the stigma was still receptive at 40.2/25.5˚C. In contrast, under controlled conditions the stigma was still receptive at 35/20˚C in four genotypes. Clearly, chickpea pollen grains are more sensitive to high temperature than the stigma in both the field and controlled environments. Among the four genotypes tested, ICC 1205 was the most heat tolerant and ICC 4567 was the most heat sensitive.

Surveys were carr~ed out to determine the prevalence of plgeonpea d~seases In the major plgeonpea growlng areas of Asla Afrlca and the Amerrcas between 1975 and In lnd~a suwcys In eleven states revealed that wllt storll~ty mosalc Phytophthora bl~ght Macrophomlna stem canker and yellow m0sa.c were econorn~cally lmportant dtseases Other dlseases were of rnlnor Importance Disease problems In Bangladesh Malays~a and Nepal were of less Importance In Afrlca wllt was a serlous d~sease tn Maiaw~ 136 3%). Tanzanla (20 4%1 and Kenya (15 9%) Leaf spot In Kenya and Malaw1 dnd powdery m~ldew In Kenya, Tanzan~a and Zamb~a were Important Other dlseases were not economically Important In the Amerlcas wltches broom Phoma stem canker and rust were the Important drseases Annual crop losses due lo the comblned effecl of w~lt and stertllty rnosalc d~seases In lnd~a were estlrnated to be worth dbout US$ 113 mlll~ons In Afrlca the estimated losses from wtlt disease alone were over US$ 5 rnlll~ons annually

Chickpea (Cicer arietinum L.) is an important food legume and heat stress affects chickpea ontogeny over a range of environments. Generally, chickpea adapts to high temperatures through an escape mechanism. However, heat stress during reproductive development can cause significant yield loss. The most important effects on the reproductive phase that affect pod set, seed set and yield are: (1) flowering time, (2) asynchrony of male and female floral organ development, and (3) impairment of male and female floral organs. While this review emphasises the importance of high temperatures >30°C, the temperature range of 32–35°C during flowering also produces distinct effects on grain yield. Recent field screening at ICRISAT have identified several heat-tolerant germplasm, which can be used in breeding programs for improving heat tolerance in chickpea. Research on the impact of heat stress in chickpea is not extensive. This review describes the status of chickpea production, the effects of high temperature on chickpea, and the opportunities for genetic improvement of chickpea tolerance to high temperatures.

High temperature is an important factor affecting chickpea growth, development and grain yield. Understanding the plant response to high temperature is a key strategy in breeding for heat tolerance in chickpea (Cicer arietinum L.). This study assessed genetic variability for heat tolerance in chickpea and identified sources of heat tolerance that could be used for crop improvement. One hundred and sixty-seven genotypes were grown in two environments (heat stressed/late sown and non-stressed/optimal sowing time) in 2 years (2009-2010 and 2010-2011) at the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Patancheru, India. Large genetic variation was observed for phenology, growth, yield components and grain yield. While phenology (assessed as days to first flower, days to 50% flowering and days to first pod) was negatively correlated with grain yield at high temperature; plant biomass, pod number, filled pod number and seed number per plant were positively correlated. Genotypes were classified into short and long duration groups based on their maturity. Days to first flowering (DFF) of long duration genotypes were negatively associated with grain yield under stressed conditions in both years compared with medium to short duration genotypes. However, genotypes varied in their heat sensitivity and temperatures ≥35 • C produced yield losses up to 39%. A heat tolerance index (HTI) classified the genotypes into five groups: (i) stable heat tolerant (>0.5), (ii) moderately heat tolerant (0.1-0.49), (iii) stable heat sensitive (−ve values), (iv) heat tolerant to moderately sensitive (−0.10 to 1) and (v) heat sensitive to moderately tolerant (−0.5 to 0.4). Pod characteristics, including days to first pod and pod number per plant, were correlated with grain yield whereas canopy temperature depression (CTD) was generally not correlated. Heat tolerant genotypes in a range of maturities were identified that could be used to improve the heat tolerance of chickpea.

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