No abstract

An application of up to 120 kg/ha of nitrogen fertilizer in the dry season improved the milling quality of the chalky varieties ‘IR8,’ ‘IR5,’ and ‘Sigadis’ but not that of the nonchalky variety ‘C4‐63.’ An application of up to 60 kg/ha of nitrogen increased the protein content of brown rice of the four varieties but increased the head rice yield of only Sigadis, the most chalky of the four varieties; the head rice yield of the other three varieties remained unchanged. Irrespective of variety and nitrogen level, the optimum time of harvest of transplanted rice for obtaining maximum grain and head rice yields and highest germination percentage was between 28 and 34 days after heading in the dry season, and between 32 and 38 days in the wet season. These heading periods correspond to moisture contents of between 22 and 19% and between 21 and 18%, respectively. Lodging increased grain yield losses in both seasons, with the losses being greater when harvested late; therefore, lodging‐susceptible varieties should be harvested earlier than lodging‐resistant varieties. Nitrogen fertilization in the dry season delayed by 2 to 4 days the optimum time of harvest of the improved varieties IR8, IR5 and C4‐63.

No abstract

Many investigators believe that when grown for the first time, the soybean [Glycine max (L.) Merr.] nodulates poorly unless inoculated with Rhizobium japonicum. However, in Nigeria the cultivar ‘Malayan,’ which originated from Indonesia, has nodulated quite well with indigenous strains of Rhizobium. We chose cultivars originating from Southeast Asia and from the USA and compared parameters associated with effective nodulation when these cultivars were grown with and without inoculation with Rhizobium japonicum. Seed inoculation with Nitragin‐S inoculant did not significantly improve nodulation, growth, amino‐N stem exudate, and yield of the Southeast Asian cultivars Malayan, ‘Orba,’ and ‘TGm 686.’ In contrast, the American cultivars ‘TGm 294‐4‐2371,’ ‘Bossier,’ and ‘Jupiter’ nodulated poorly without inoculum, and showed increases in growth of 36 to 47% and seed yield of 40 to 97% when inoculated. However, the American cultivars generally have better agronomic characteristicsa and higher yield potential than the Southeast Asian cultivars. It is, therefore, important to combine the desirable characteristics of these two distinct groups of soybean cultivars in the breeding program to develop improved cultivars suitable for and adapted to tropical environments.

SUMMARYField experiments were conducted at the International Institute for Tropical Agriculture, Ibadan, Nigeria, during two cropping seasons, with two cultivars of climbing cow peas (Vigna unguiculata (L.) Walp. subspecies sesquipedalis) cv. FARV-13 and TVU-1209. The work investigated their yields when intercropped with maize, which served as live support.The results showed that there were varietal differences in the cow-pea response to method of planting. Under the intercropped systems, highest dry-matter yield was obtained when TVU-1209 was planted on the same hill with maize while similar yields were obtained with FARV-13 planted in alternate hills with maize. TVU-1209 did not increase maize lodging except when planted in alternate hills with maize, but FARV-13 significantly increased maize lodging under all planting methods. Consequently, FARV-13 reduced maize yields more than TVU-1209.Neither pod length nor pod weight was affected by the planting. Highest yields from both cow pea and maize combined were realized from TVU-1209 planted between rows of maize. The yield of FARV-13 cow pea intercropped with maize did not show any advantage due to intercropping over sole crop of each.