Pigeon pea (PP), Cajanus cajan, is a plant that is cultivated for human food and animal feed. It exists as a wide range of cultivars, and their flexibility for use in animal rearing systems have made PP popular, especially for small-scale farmers. PP is grown widely in India and in parts of Africa and Central America. The main producers of PP in the world are India, Uganda, Tanzania, Kenya, Malawi, Ethiopia, Mozambique, the Dominican Republic, Puerto Rico, the West Indies in the Caribbean and Latin America region, Indonesia and the Philippines and Australia. Analysis has shown that PP contains 17.9-24.3% crude protein (CP) in whole grain, and 21.1-28.1% in split seeds, and high protein genotypes contain 32.5%. Optimal levels of utilisation have been shown to improve broiler performance and may reduce daily feed cost. However, PP contains anti-nutritional factors that negatively affect feed efficiency. The use of processing methods such as fermentation, boiling, milling, soaking, and roasting can minimise any harmful effects and improve its nutritive quality, positively enhancing performance parameters. Studies on the use of PP suggested that it can be included at 7.5% of the diet or as 50% substitution for soybean meal in broiler diets.

To assess the impact of the carpenter bee, Xylocopa olivacea Fabricius 1787, on the pod and seed yields of Cajanus cajan (L.) Millsp. 1900, in this study, its foraging and pollinating activities were examined in Nkolbisson during two seasons (July 2008–January 2009 and June–December 2009). Observations were made on 180 inflorescences per treatment. The treatments included unlimited floral access to all visitors, bagging of flowers to prevent access to all visitors, and floral access to limited visits by X. olivacea only. In addition, information on all floral visitors was recorded. The carpenter bee's seasonal rhythm of activity, its foraging behaviour on flowers, its pollination efficiency, the fruiting rate (Fr) and the number of seeds per pod were recorded. Nineteen species of insects were recorded visiting the flowers of C. cajan.Chalicodoma cincta cincta was the most prominent one, followed by X. olivacea, Apismellifera adansonii, Megachile bituberculata and Xylocopa albiceps, and the bees were the most frequent floral visitors. Xylocopa olivacea mainly foraged for nectar and pollen and its foraging speed was 11.75 flowers/min. The Fr, the number of seeds/pod and the percentage of normal seeds of unprotected inflorescences were significantly higher than those of inflorescences protected from insects. The foraging activity of X. olivacea resulted in a significant increase in the Fr by 22.26%, as well as the number of seeds/pod by 34.98% and the percentage of normal seeds by 12.09% in the two study years. Placing X. olivacea nests close to C. cajan fields is recommended to increase pod and seed production in Cameroon.

The spotted pod borer Maruca vitrata (Geyer) is known for its economic importance throughout its geographical distribution because of its destructive nature to reproductive parts of several grain legume crops including pigeonpea. In view of the importance of the pest, the present study was carried out on the association of different morpho-chemical traits with resistance/susceptibility to M. vitrata at the International Crops Research Institute for the Semi-Arid Tropics, Patancheru, India. Trichome length and density, sugars, proteins and phenols were found to be associated with resistance to M. vitrata in short-duration pigeonpea genotypes. Pod damage by M. vitrata on different short-duration pigeonpea genotypes in the field ranged from 5.8 to 68%. Laboratory studies showed less consumption of food and reduced larval and pupal weights of M. vitrata when reared on the resistant genotypes ICPL 98003 and ICPL 98008 indicating antibiosis effects of the genotypes. Trichome density on upper and lower surfaces of the leaf (390 and 452/9 mm2), and length (3.5 mm) and trichome density (442/9 mm2) and length (5.9 mm) on pods were found positively correlated with the resistant genotype ICPL 98003. High sugar content in flowers (22%) and pods (10.6%) was responsible for the susceptibility of ICPL 88034, while high phenol concentration in flowers (6.5%) and pods (9.3%) in ICPL 98003 was responsible for resistance. Protein content in pods was significantly higher (25.5%) in susceptible ICPL 88034 when compared with resistant ICPL 98003 (16.5%). Based on these results, ICPL 98003 and ICPL 98008 were categorized as highly resistant and ICPL 98012 as moderately resistant. This paper discusses the physico-chemical traits associated with resistance to M. vitrata in short-duration pigeonpea genotypes.

We analysed the patterns of variation for 14 qualitative and 12 quantitative traits in 11,402 pigeonpea germplasm accessions from 54 countries, which were grouped into 11 regions. Semi-spreading growth habit, green stem colour, indeterminate flowering pattern and yellow flower colour were predominant among qualitative traits. Primary seed colour had maximum variability and orange colour followed by cream were the two most frequent seed colours in the collection. Variances for all the traits were heterogeneous among regions. The germplasm accessions from Oceania were conspicuous by short growth duration, short height, fewer branches, pods with fewer seeds, smaller seed size and lower seed yields. The accessions from Africa were of longer duration, taller, with multi-seeded pods and larger seeds. The germplasm diversity indicated by Shannon–Weaver diversity index (H′) pooled over all traits, was highest for Africa (0.464±0.039) and lowest for Oceania (0.337±0.037). The cluster analysis based on three principal component scores using 12 quantitative traits revealed formation of three clusters: cluster 1 includes accessions from Oceania; cluster 2 from India and adjacent countries; and cluster 3 from Indonesia, Thailand, the Philippines, Europe, Africa, America and the Caribbean countries. Pigeonpea-rich countries such as Myanmar, Uganda, and others like Bahamas, Burundi, Comoros, Haiti and Panama are not adequately represented in the collection, and need priority attention for germplasm exploration.

In the present work, influence of food plants on different life table parameters of the parasitoid Trioxys indicus Subba Rao and Sharma was studied as affected through its host Aphis gossypii Glover. Age-specific survival of T. indicus on aphids bred on Lagenaria vulgaris was greater (7 days) than on Luff a cylindrica and Cucurbita maxima (4 days). The net fecundity rate, total reproductive period, intrinsic rate of natural increase, intrinsic rate of total fecundity and weekly multiplication rate of T. indicus fed on L. vulgaris was higher than on other cucurbit food plants. Doubling time of the parasitoid fed on L. vulgaris was lower than on other food plants, whereas the mean generation time of the parasitoid on L. vulgaris was slightly higher than on L. cylindrica but lower than on Cajanus cajan and C. maxima. All these measurements (considered indices of fitness of the entomophages) indicated that population growth pattern of T. indicus fed on L. vulgaris is faster than those fed on other food plants.

The differential attraction by 2 pigeonpea cultivars has been tested through the oviposition behaviour of Heliothis armigera females in a standardized laboratory assay. Seedlings of a susceptible variety (PPE-50) are under choice conditions significantly more attractive at a distance, and without contact allowed other than those of the resistant variety (PPE-45). The volatile signal is contained in the hexane extract from PPE-50 leaves, as shown in the oviposition assay, and after vacuum distillation is present in the more volatile fractions of the mono- and sesquiterpenoids. These compounds, which are also contained in the hexane extracts of 2 more pigeonpea cultivars, a check of medium susceptibility (T-21) and a wild relative (Atylosia scarabaeoides), were compared by capillary gas chromatography. The 4 pigeonpea varieties were characterized by their specific aromagrams, a method which may also advantageously be used in pigeonpea breeding programs.