Variation for natural out-crossing in pigeonpea

Summary Several researchers have reported a considerable degree of natural out-crossing in pigeonpea from different environments. This paper reviews the subject with respect to the variation for natural out-crossability, pollinating vectors, extent of natural out-crossing, isolation specifications, and the possible utilization of natural out-crossing in pigeonpea improvement.ICRISAT Journal Article No. 831.     

Chromosome 1D as a possible location of a gene (s) controlling variation between wheat (Triticum aestivum L.) varieties for carbon isotope discrimination (Δ) under water-stress conditions

Cytoplasmic male-sterility (CMS) in pigeonpea has been reported when some wild relatives of pigeonpea were crossed as the female parent with cultivated types as the male parent. In this paper we report a new source of CMS developed by using the cultivated pigeonpea as the female parent and one of its wild relative Cajanus acutifolius as the pollen donor. This is the first report in pigeonpea where CMS has been developed using the cytoplasm of cultivated pigeonpea. Several pure line cultivars of pigeonpea restored pollen fertility whereas cv. HPL 24 partially maintained male-sterility. The wild species C. acutifolius used as one of the parents, maintained complete sterility. Cytological analysis revealed that both in male-sterile as well as the fertile floral buds, meiosis proceeded normally till the tetrad stage. However in the male-sterile genotypes during the formation of tetrads, the pollen mother cell (PMC) wall did not dissolve to release the tetrads unlike in the fertile genotypes and this major event was found to be responsible for male-sterility.     

Effect of heat treatments on trypsin/chyomotrypsin inhibitor activity of red gram (Cajanus cajan L.)

The application of dry heat to the seeds and meal was not effective in inactivating the trypsin inhibitory activity (TIA) and chymotrypsin inhibitory activity (CIA). Soaking for 24 hours followed by cooking for 20 min was effective in destroying the TIA and CIA.     

Pinostrobin from Cajanus cajan (L.) Millsp. inhibits sodium channel-activated depolarization of mouse brain synaptoneurosomes

This investigation focuses on the in vitro neuroactive properties of pinostrobin, a substituted flavanone from Cajanus cajan (L.) Millsp. of the Fabaceae family. We demonstrate that pinostrobin inhibits voltage-gated sodium channels of mammalian brain (IC₅₀ = 23 µM) based on the ability of this substance to suppress the depolarizing effects of the sodium channel-selective activator veratridine in a synaptoneurosomal preparation from mouse brain. The resting membrane potential of synaptoneurosomes was unaffected by pinostrobin. The pharmacological profile of pinostrobin resembles that of depressant drugs that block sodium channels.     

贵州木豆病虫害发生特点及危害程度

为摸清木豆病虫害在贵州种植区的发生危害情况,采取多点多次抽样法对贵州省木豆病虫害发生情况进行了调查,并收集标本进行室内分类鉴定.结果:共鉴定出病害5种,其中真菌性病害4种,病毒性病害1种;害虫39种,其中昆虫纲7目19科37种,蛛形纲1目2科2种.着重介绍了在贵州种植区危害较重的3种病害、6种虫害的生物学特征及危害特点.可为贵州省木豆大面积推广种植及病虫害防治提供参考依据.     

Induction of phytoalexins in pigeonpea (Cajanus cajan) in response to inoculation with Fusarium udum and other treatments

Cajanol accumulation was monitored in four cultivars of pigeonpea, Cajanus cajan (L) Millsp, after inoculation with 2 x 10(6) conidia ml-1 of Fusarium udum Butler. Rapid accumulation was observed only in wilt-resistant cultivar ICP 9145. Another wilt-resistant cultivar, ICP 8863, had low levels of cajanol similar to those in wilt-susceptible cultivars ICP 2376 and Malawi local, indicating that rapid cajanol accumulation is not positively correlated with resistance to wilt in pigeonpea. A comparison of various inducing agents showed live conidia of the pathogen to cause more rapid accumulation than the other agents.     

Planted legume fallows reduce weeds and increase soil N and P contents but not upland rice yields

Shortened fallows have resulted in declining upland rice yields in slash-and-burn upland rice systems in northern Laos. We studied the benefit of planted legume fallows for rice productivity, weeds, and soil nitrogen and phosphorus availability. Four systems were evaluated over a 5-year period: 1-year fallow with native species, 1-year Cajanus cajan fallow, 1-year Leucaena leucocephala fallow, and continuous annual rice cropping. Rice was grown either once each year as continuous annual cropping or in alternate years of 2001, 2003, and 2005. C. cajan and L. leucocephala were sown with rice during the 2001 growing season. In subsequent years, L. leucocephala regenerated from root stock and did not have to be resown, whereas C. cajan was resown in 2003. Establishment of either C. cajan or L. leucocephala had no significant effect on rice yield in 2001, and rice yields ranged from 2.0 to 2.3 t/ha. Rice yields declined rapidly in succeeding years, and rice yields in the four systems ranged from 0.7 to 1.1 t/ha in 2003 and from 0.3 to 0.5 t/ha in 2005. Although two planted fallow systems increased nitrogen input because of greater biomass accumulation in 2003 and 2005 and soil phosphorus availability was higher following L. leucocephala fallow in 2005, there were no significant differences in rice yields among the four systems in either year. Weed biomass during the rice growing season increased each year in all systems and increased more rapidly for continuous annual rice cropping, in which the dominant weed species was Ageratum conyzoides L. Among the other three systems, there were no significant differences in the weed biomass in 2003 and 2005. We conclude that C. cajan and L. leucocephala as 1-year fallows do not offset the negative effects of increased cropping intensity on rice yield in this region.