Study the morphophenological characteristics, growth indices, yield and yield components of promising drought tolerant chickpea (Cicer arietinum L.) genotypes under supplementary irrigation in Nishabour

Introduction In the region of Khorassan, chickpea often is sown traditionally at the end of the rainy season (March or April) based on the moisture stored in the soil. On the other hand, the amount and distribution of rainfall during the growing season is also very unsuitable. Therefore, the plants usually encounter intermittent drought stress during the vegetative growth and in the reproductive growth stage and may meet terminal drought stress and heat, simultaneously; resulting in a disturbance on pollination and assimilate the seed that leads to severe yield reduction. In these areas, the synchronization critical stages of plant phenology with adequate moisture in the soil is important. So, the selection of genotypes that their life cycle is completed before the heat and drought occurrence at the end of the season, is considered as a first step to improve the chickpea production under rainfed conditions.   Materials & Methods In order to evaluate the morphophenological characteristics, yield and yield components of promising drought tolerant chickpea (Cicer arietinum L.) genotypes under supplementary irrigation, this study was carried out in Educational-Researching Farm of Shahid Rajaei, College of Agriculture in Neyshabour during 2010-2011. This study was performed based on Randomized Compelete Blocks Design with five promising chickpea drought tolerant genotypes (MCC80, MCC352, MCC392, MCC537 and MCC696) and two genotypes as control (ILC482 and Karaj 12-60-31) with four replications. Seeds were prepared from seed bank of Research Center for Plant Sciences, Ferdowsi University of Mashhad (Mashhad Chickpea Collection; MCC). Planting operations was performed in April 2011. Planting density was 30 plants.m-2 and row spacing was 50 cm. Two times irrigation as supplementary irrigation were applied at planting and flowering stages. Some characteristics such as days from planting to 50% of emergence, flowering and podding; plant height; primary and secondary branches number per plant; leaf area index (LAI); crop growth rate (CGR); relative growth rate (RGR); seed yield and yield components (pods number per plant and 100Seed weight) were measured.   Results & Discussion Based on the results, there were significantly differences among genotypes for all traits. Genotypes MCC80, MCC696, MCC392 and MCC537 had the lowest and genotypes MCC358 and MCC252 had the highest number of days from planting to flowering, in which the difference between them was significant (P≤0.05). MCC80 had the lowest plant height and MCC537 and MCC392 showed the highest. MCC80 and MCC358 had the highest and lowest number of pods per plant, respectively. It seems that MCC80 growth would avoid collisions with high temperatures and consequently the flowering has taken place in lower temperatures and higher soil moisture. The above factors led to a reduction of the failure of flowers, so the number of pods per plant increased in MCC80 (23 pods) significantly, compared other genotypes. Based on the results, on both grain yield per plant and seed yield, genotypes MCC252 and MCC358 showed the lowest and MCC80 had the highest rate.   Conclusion Although Karaj12-60-31 (MCC358) as a commercial genotype, showed the highest plant height and growth indices, but for traits such as number of pods per plant, 100 seed weight and seed yield, was poor. The results showed that MCC80 with 970 Kg.ha-1 had the highest seed yield and ILC482 (MCC252) and Karaj12-60-31 (MCC358) had the lowest. The average yield for the MCC80 with supplementary irrigation in this region, was twice more than the yield in rainfed and 75% of yield in irrigated conditions in the region. However, the seed yield of commercial genotypes of Karaj12-60-31 (MCC358) and ILC482 (MCC252), were 324 and 320 Kg.ha-1 respectively. Totally, we recommend the repetition of such tests in this ares; in addition we can consider the genotypes such as MCC392, MCC352 and especially MCC80 as promising chickpea drought tolerant genotypes with supplementary irrigation during flowering in this area.