2010 Annual Report 1a.Objectives (from AD-416) Exchange pigeonpea germplasm for sustainable cereal-legume cropping systems suitable for the southern Great Plains region. 1b.Approach (from AD-416) Identify and exchange Pigeonpea cultivars suitable for the summer fallow period in a continuous winter wheat production system. Evaluate pigeonpeas as forage or forage/grain crop for the utilization by humans and/or livestock under the climatic conditions of the Southern Great Plains. Provide detailed climatological data for El Reno, Oklahoma, to ICRISAT. 3.Progress Report Tropical legumes offer potential forage and grain that can be grown during summer fallow period in the continuous winter wheat production systems typical of the southern Great Plains region. Earlier research demonstrated that pigeon pea is drought tolerant and produces abundant quantities of high-quality forage as well as grain. Pigeon pea hybrid germplasm previously supplied by ICRISAT had a slightly longer growing period and did not mature before freezing temperatures occur at this location. The new hybrid lines developed at ICRISAT seem to be not early enough to produce seed in this region. Pigeon pea forage contains anti-nutritional compounds during the vegetative period, and these compounds are lower at flowering and early pod stages of development. Recent grazing studies by sheep at ICRISAT have shown that ICPL 88034 line showed an improvement in forage utilization and weight gain by sheep. ICPL 88034 seed was obtained from ICRISAT and a seed multiplication experiment was initiated in 2010. Once enough seed is produced a grazing study will be conducted. ICRISAT continues to provide information and assistance in developing new cultivars suitable for the southern Great Plains region. The ADODR monitors the activity of this agreement through meetings and conference calls.