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Wheat Information Service
Number 74: 25-27 (1992)


A note on drought resistance in wheat

R. K. Chowdhury

Department of Plant Breeding, Haryana Agricultural University, Hisar-125004, India.


Breeding major food crops for stable yields under drought and rainfed stress environments has become a subject of major interest (Fischer et al 1982). Various mechanisms imparting drought resistance like escape, endurance, avoidance and tolerance etc have been put forward by various workers. However, still plant breeders are largely guided by the grain yield response in selecting for drought resistance due to lack of well defined informations on the above mechanisms. The black box approach, ie, testing of performace of genotypes under stress situation is a very useful step in breeding programmes mainly because it allows a direct estimate of drought resistance of susceptibility of individual genotypes.

Although stricking increases have been achieved in the wheat yields all over the world with the development of modern high yielding and high input responsive varieties after the introduction of dwarfing genes of Norin 10, however, yields under drought and rainfed conditions are still low and stagnant. The rainfed wheats accounts for about 35 per cent of the total acreage of wheat in India, therefore, it would be desirable to screen the genotypes under rainfed conditions so that the best or better genotypes could be identified and utilized in future breeding programmes.

Having this in mind, a total of 115 genotypes of wheat including aestivum and durum. mostly taken from "National Drought Screening Nursery" were screened for their yield performance at Haryana Agricultural University, Regional Research Station, Bawal for three years; 1979-80, 1980-81 and 1981-82 to identify variations best suited under drought/rainfed conditions. Bawal is situated in South-Western part of Haryana State. The climate in this zone is semi-arid with very erratic rainfed. The soil is loamy sand, weakly alkaline (pH 7.8), bulk density 1.45 g/cm3 having 84.6% sand, 6.7% silt and 8.7% clay. The data were recorded on grain yield/m row length (g) and total dry matter produced, ie, biological yield/m row length (g). The harvest index (%) was calculated by dividing grain yield with total biological yield.

Genotypic differences were found highly significant for all the three characters studied in the present study (grain yield, biological yield and harvest index) indicating, thereby, that sufficient genotypic variability existed in the material. Based on the results of three years on grain yield, 15 varieties have been identified which yielded consistantly good. Their data are presented in Table 1. These varieties appeared to be the most drought tolerant or can give good yields under drought/rainfed conditions particularly South-Western part of Haryana State. Many of these varieties have been recommended for commercial cultivation under drought/rainfed conditions in various states in India like, C306, NI 5439, Narbada 4, WL 410 etc and also have been identified better under drought by Chowdhury and coworkers while studying 60 wheat genotypes under six varying levels of irrigations under Bawal conditions. Chowdhury et al (1985) reported C306, Narbada112, N 7231 and HI 617 as the outstanding varieties under zero irrigation. While studying stability parameters, Chowdhury et al (1985) indentified varieties Narbada112 and N 7231 suitable for poor environment. Variety C306 appeared to be the stable over wide range of environments. Chowdhury et al (1986) also, reported low/moderate drought susceptibility indices(s) for some of these varieties. Those having s below 0.7 as least drought susceptible or most drought tolerant ones were NI 5749, HS32, MP 823 A and HD 2037 while moderately drought tolerant ie having s value between 0.7 to 1.0 were NI 5439, K7527, HP1258, N 7231, Narbada112 and MP195. Based on drought susceptibility index and productivity under drought environment varieties Narbada 4, and HS 82 were found to be best for drought conditions. There were varieties like C306, Narbada112, N 7231, HI 617 and NI 5749, which had s value on higher side, but gave higher yields under drought conditions and thus were best for drought environment. The drought susceptibility index of variety C306 was also reported between 0.91 to 1.08 by Fischer and Maurer (1978).

The results of the present study also showed that the grain yield was contributed mainly by the total biological yield in most of the varieties. Chowdhury et al (1985) also reported that grain yield was mainly contributed by total biological yield. The studies also showed the correlation of grain yield with plant height, total biological yield and harvest index.


References

Chowdhury RK, Arya AS and Paroda RS (1985) Drought resistance in Wheat. III Grain yield responses. Proc 3rd Nat Sem Genet Wheat Improv, 8-10 May, 1985, Shimla, India.

Chowdhury RK, Paroda RS and Singh BP (1985) Drought resistance in Wheat. I Grain yield responses and its correlation with grain yield compontents. Genetics Agr 39: 131-142.

Chowdhury RK, Arya AS and Parods RS (1988) Drought susceptivility indices and grain yield in bread wheat. Genet Agr 42: 177-186.

Fischer KS, Johnson EC and Edmeads HO (1982). Breeling and selection for drought resistance in tropical maize. In 'Drought Resistance in crops with emphasis on Rice'. (IRRI: Los Banos, Phillippines): 337-400.

Fischer RA and Maurer R (1978) Drought resistance in spring wheat cultivars. Grain yield response. Aust J Agric Res 29: 897-912.

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