Breeding for increased water use efficiency in chickpea

Water use efficiency (WUE) is a complex trait, hence secondary traits which are genetically associated with WUE and have a positive association with yield, easy to measure and have genetic variation can be used as breeding targets for high WUE. The aim of the present study was to discover the variation for water use efficiency and grain yield in different tillage and irrigation regimes; the basis of yield formation under water limited conditions and develop a chickpea ideotype. The field experiment was conducted at the Plant Breeding Institute, the University of Sydney in Narrabri, northwest New South Wales in Australia. A total of 36 entries were planted replicated twice under well-watered and water-stress conditions, and no-till and till regimes. Water use was monitored using a neutron probe moisture meter and water use efficiency calculated using the soil water balance method. Grain yield was higher under irrigation at 1722 kg/ha than rainfed conditions at 1478 kg/ha. No-till had 7.4% higher yield than the till regime. WUE was higher under no-till (5.02 kg/ha/mm) than under till (4.87 kg/ha/mm) and higher under irrigation (5.05 kg/ha/mm) than under rainfed conditions (4.84 kg/ha/mm). There was a strong association between grain yield and WUE under rainfed conditions, thus high yielding genotypes had high WUE. Sonali had the highest yield and WUE. Normalised difference vegetation index (NDVI) at early podding and late podding and chlorophyll content at late podding were useful marker traits in identifying genotypes with potentially high yield and high drought tolerance. Sonali, ICCV 96853 and PBA Slasher were identified as drought tolerant genotypes. The constructed chickpea ideotype had higher yields than the commercial varieties and had 76% resemblance to Sonali. By incorporating key target traits and targeting the right environment, chickpea yields can be sustained under soil water limited conditions

Evaluation of chickpea genotypes for resistance to Ascochyta blight (Ascochyta rabiei) disease in the dry highlands of Kenya

Chickpea (Cicer arietinum) is an edible legume grown widely for its nutritious seed, which is rich in protein, minerals, vitamins and dietary fibre. It’s a new crop in Kenya whose potential has not been utilized fully due to abiotic and biotic stresses that limit its productivity. The crop is affected mainly by Ascochyta blight (AB) which is widespread in cool dry highlands causing up to 100% yield loss. The objective of this study was to evalu- ate the resistance of selected chickpea genotypes to AB in dry highlands of Kenya. The study was done in 2 sites (Egerton University-Njoro) and Agricultural Training centre-ATC-Koibatek) for one season during long rains of 2010/2011 growing season. Thirty six genotypes from reference sets and mini-core samples introduced from ICR- SAT were evaluated. There were significant (P<0.001) differences in AB responses and grain yield performance in test genotypes in both sites. AB was more severe at Egerton-Njoro (mean score 5.7) than ATC-Koibatek (mean score 4.25), with subsequent low grain yield. Genotypes ICC7052, ICC4463, ICC4363, ICC2884, ICC7150, ICC15294 and ICC11627 had both highest grain yield in decreasing order (mean range 1790-1053 Kg ha-1) and best resist- ance to AB. Further evaluation is needed in other multi-locations and their use in breeding program determined especially because of their undesirable black seed color. Commercial varieties (LDT068, LDT065, Chania desi 1, and Saina K1) were all susceptible to AB, but with grain yield >1200 Kg ha-1. The findings of the study showed that chickpea should be sown during the short rains (summer) in the dry highlands of Kenya when conditions are drier and warmer and less favorable for AB infection. However yield could be increased by shifting the sowing date from dry season to long rain (winter) thus avoiding terminal drought if AB resistant cultivars with acceptable agronomic traits could be identified