www.IndianJournals.com Members Copy, Not for Commercial Sale Downloaded From IP - 210.212.95.210 on dated 22-Sep-2015 Indian J. Genet., 68(4): 373-379 (2008) Genetic improvement for deficit irrigation in bread wheat ( Triticum aestivum L.) D. Mohan 1 , P. C. Mishra 2 , S. C. Misra 3 , B. S. Jadon 4 , P. N. Rasal 5 and B. K. Meena 1 1 Directorate of Wheat Research, Karnal, 2 JNKVV, Powarkheda, 3 ARI, Pune, 4 SDAU, Vijapur, 5 NPKV, Niphad (Received: March 2008; Revised: October 2008; Accepted: October 2008) part of the country is either grown on residual moisture or irrigations are restricted to just one or two and the irrigation source is mostly a well which usually goes dry after 2-3 months of monsoon rains. This water source is often utilised by the farmers to apply irrigation at the most crucial time which is identical to CRI stage, the most crucial stage in wheat under deficit irrigation [6]. This kind of abiotic stress, occurring predominantly in the vegetative phase adversely affects tillering, biomass production, grain number and poor grain filling. To strengthen wheat breeding for such situations, it is essential to access the character response of supplementary irrigation and define the plant type required for restricted irrigation so that effective selection could be exercised in the segregating materials. The route to yield under moisture stress conditions should also be investigated to identify the key components of grain yield. The present investigation focused these issues in the targeted area so as to develop the kind of wheat genotypes, truly essential to harness advantages of restricted irrigation. Material and methods The study conducted at three locations during 2000- 04, involved an experiment in the first two years, which was conducted to compare crop performance under moisture stress conditions. A multilocation trial was conducted in the next two years to access the genetic yield potential under one irrigation situation and select the desirable genotypes. The material used in the study was selected on the basis of preliminary screening under restricted condition at Karnal. The experiment was laid in split plot design with two irrigation levels (zero and one) as main plots and twelve genotypes as sub-plots. The experiment was planted at Powarkheda in Madhya Pradesh, Pune in Maharshtra and Vijapur in Gujarat. With pre-sown irrigation, planting was done under Abstract A study was conducted for four years in the central and peninsular India to examine the route to yield under deficit irrigation in bread wheat and devise suitable selection criteria for variety development. Yield components and genotypes were compared at two irrigation levels (zero and one) in the first two years whereas trials were conducted in the following two years to realize the yield potential and genotype specificity under supplementary irrigation. Majority of the yield governing traits responded to the supplementary irrigation but the magnitude of realized advantage varied vividly in the associated traits. In yield determinants; biomass, stem elongation rate, spike weight and a disincentive to plant height was common in both treatments. Delayed heading in zero irrigation and longer duration but quick grain ripening for one-irrigation were additional attributes of selection. Proper site selection and screening of the germplasm was found crucial to raise prospects of high genetic yield potential under deficit irrigation. Key words: Deficit irrigation, limited irrigation, moisture tolerance, yield parameters, selection criteria, Indian wheat Introduction Efficient use of restricted water resources under irrigated agriculture is paramount in tropical or semiarid environments. Studies in Turkey and Iran have revealed that exposing wheat crop to water stress at specific growth stages may not cause significant yield reduction [1, 2]. Response to limited irrigation in wheat had been examined in several countries and water saving strategies had been suggested/ formulated in China, WANA region and Australia [3-5]. Specific wheat varieties for limited irrigation (Promontory, TAM 107 and Thunderbolt) have been recommended in USA, too. In central and peninsular India, nearly 4.0-4.5 m ha area of this prominent winter cereal i.e. bread wheat (Triticum aestivum L.) falls in the water deficit area. Wheat in this