Early embryogenesis up to 8 days after pollination was characterized in V. unguiculata. When crosses were performed between V. unguiculata and wild V. vexillata, seeds were not obtained due to crossability barriers. In most cases pollen tube growth was arrested in the stigmatic tissue. In the 15-20% of ovules which were fertilized, embryo development was normal up to the globular stage, but then (5-8 days after pollination) the embryo began to collapse.

In Italy cowpeas are grown primarily for green pod production. During 1986-88, 3 collecting missions covering the regions of Campania, Basilicata, Apulia and Calabria were mounted by the Germplasm Institute, Bari. A total of 177 seed samples were collected (147 of cowpeas and 30 of asparagus beans (V. unguiculata subsp. sesquipedalis)) from 120 sites. Severe genetic erosion was noted, particularly in Basilicata and Calabria, due to farmers no longer growing the crop or using seed from commerical ...

Phenolic compounds were analysed in leaf samples from 9 lines known to be resistant or susceptible to aphids (mainly Aphis craccivora but also, to a lesser extent, A. fabae). Resistant lines TVu3000, IT84E and IT83S742 had higher flavonoid glycoside contents than the susceptible lines VITA7, TVu3236 and IT82E. In the other 3 lines there was no clear relationship, which was attributed to sampling errors. Some of the phenolic compounds identified were tested in feeding experiments with A. fabae. The ...

Data are given on seed characteristics and nutritive value for 6 accessions of 4 wild Vigna taxa (V. vexillata, V. oblongifolia, V. gracilis and V. unguiculata subsp. dekindtiana) and 27 cultivated V. unguiculata varieties. The 100-seed weight ranged from 2 to 6 g among wild and from 6 to 24 g in cultivated accessions. Protein content was significantly lower in cultivated than in wild accessions (22.3-25.5% vs. 23.4-28.2%) while the reverse was true for in vitro protein digestibility (79.5-82.5% ...

Trypsin inhibitor content was determined in the seeds of 21 cowpea (Vigna unguiculata) lines (10 known to be resistant to Callosobruchus maculatus and 11 susceptible) whilst fatty acid composition was determined in 58 lines (11 resistant and 47 susceptible). A wide range in trypsin inhibitor contents was observed but these were not related to level of resistance. Total unsaturated fatty acid contents, however, were associated with resistance level, being lowest in the resistant lines. Six fatty ...

A discussion is given of control of weeds of root and tuber crops, such as cassava, sweet potatoes, yams and cocoyams [Colocasia esculenta], as part of an integrated pest management programme.

Nitrogen fixation by leguminous trees contributes nitrogen to agroforestry systems and enables farmers to grow their own nitrogen fertilizer. Estimation of the amount of nitrogen fixed is necessary to asses the value of leguminous trees. In the present paper, the difference method and the 15N isotope dilution method are used to calculate the amounts of nitrogen fixed in the first year by Leucaena leucocephala (with and without inoculation with Rhizobium), Gliricidia sepium and Albizia lebbeck.