Peanut genotypic variation in transpiration efficiency and decreased transpiration during progressive soil drying

Peanut (Arachis hypogaea L.) is commonly grown on sandy soils in warm climates where water-deficit can impose a limitation on yield. Identification of plant traits related to increased productivity under water-deficit conditions could be used to increase yields in these water-limited environments. Two traits were examined among 17 peanut genotypes. Transpiration efficiency (TE), ratio of mass increase to water transpired, was the first trait examined. TE was measured both under well-watered conditions (greenhouse) and soil drying (outdoors in pots) conditions. Virtually no difference was observed in TE among genotypes under well-watered conditions indicating the gas exchange properties were similar. However, under soil drying conditions there were substantial differences among genotypes. These results indicated that TE with drying soil might interact with traits associated with water loss on drying soils. Therefore, the second trait examined in this study was the fraction transpirable soil water (FTSW) content at which the decline in transpiration with soil drying was observed. This greenhouse experiment showed large variability among the 17 genotypes. A second-order polynomial described the relationship between TE under soil drying conditions and the threshold for the decline in transpiration. The FTSW for maximum TE was 0.55, but this value is expected to depend on the environmental conditions to which the plants influence TE.     

Phenotypic and genotypic characterization of bovine mastitis isolates of Staphylococcus aureus for biofilm formation

Staphylococcus aureus is one of the most common pathogens responsible for contagious mastitis in ruminants. The ability of S. aureus to form biofilm in vivo is considered to be a major virulence factor influencing its pathogenesis in mastitis. The objectives of the study were to examine in vitro slime production, biofilm formation, and the presence of the ica gene locus and icaA and icaD genes in S. aureus isolates from bovine mastitis. Thirty-two of the 35 isolates tested produced slime on Congo red agar, whereas only 24 of the isolates were found to produce biofilm in vitro. However, all the 35 isolates possessed the ica locus, icaA and icaD genes. This study indicates a high prevalence of the ica genes among S. aureus mastitis isolates, and their presence is not always associated with in vitro formation of slime or biofilm. A combination of phenotypic and genotypic tests is recommended for investigating biofilm formation in S. aureus.     

New report of Citrus indica Yu. Tanaka,a wild progenitor species of citrus from Dailong Forest,Manipur, and recommendation for its conservation

Genetic Resources and Crop Evolution - Citrus indica Yu. Tanaka is a wild and endangered progenitor species of citrus endemic to North East (NE) India. It is reported to be restricted to Nokrek...     

Applications of Genie Male Sterility in Plant Breeding

The possible applications of genie male sterility (GMS) in plant breeding arc reviewed and discussed. The basic contribution of GMS is that it provides a means of genetic emasculation which can be applied for the massive production of hybrids. There are two main fields of application: (1) the production of hybrid varieties and (2) inter- and intraspecific hybridization and back-crossing programmes for the introduction of genetic variation into crop varieties. Several schemes have been proposed for using GMS in hybrid breeding in different crops. These are discussed under four headings: genetic methods, cy-togenetic methods, temporary restoration of fertility and manual pollination. The application of GMS in hybridization intended for the introduction of alien genes is discussed as well as factors affecting the pollination of genie male steriles.     

Effects of Bacillus subtilis metabolites on larval Aedes aegypti L

The culture supernatant of a strain of Bacillus subtilis isolated from soil samples killed larvae of the mosquito Aedes aegypti. The metabolites produced by B. subtilis were characterized using high performance liquid chromatography (HPLC). Mortality rate was dose-dependent for all larval instars of A. aegypti. Log probit analysis (95% confidence level) revealed an LC₅₀ of 1.73 and an LC₉₀ 3.71 μg/ml. Molecular weights/masses of B. subtilis metabolites were confirmed using SDS–PAGE analysis. B. subtilis metabolites were confirmed using HPLC analysis. We demonstrate that secondary metabolites from B. subtilis have larvicidal activity against A. aegypti and may be suitable for the control of this and other mosquito vectors of human disease. The larvae to the metabolites, significant reduction in the activities of acetylcholinesterse, α-carboxylesterase, and acid phosphatases were recorded.     

某些植物碎叶在防治木豆线虫Rotylenchulus eni formis中的应用效果

肾形线虫Ｒｏｔｙｌｅｎｃｈｕｌｕｓｒｅｎｉｆｏｒｍｉｓ是印度木豆的主要害虫。相传某些土著植物有杀虫功效。因此，将Ａｒｇｅｍｏｎｅ，Ｃａｌｏｔｒｏｐｉｓ，Ｃａｓｔｅｒ，Ｍｅｒｉｇｏｌｄ，Ｍｕｓｔａｒｄ，Ｎｅｅｍ，Ｐａｒｔｈｅｎｉｕｍ，Ｓａｒｉｆａ，Ｓｅｓａｍｕｍ和Ｍａｈｕａ共１０种植物的碎叶按０．０６７ｈｍ￣２的１０００ｇ±１００ｇ的施用量施入土壤中并于玻璃网房中播种了两个木豆品种。每钵接种２５０个线虫卵囊，未施碎叶组同样进行接种作为试验对照。观测了接种后４５ｄ时植物生长量和线虫总量等，发现楝叶处理组木豆生长量最大。与对照相比，１０种植物碎叶处理均显著地抑制线虫卵襄的形成。     

Effect of nitrogen fertilization on the nutritional quality of wheat variety,Yecora Rojo

The effects of N-fertilization on the nutritional quality of short-straw wheat variety, Yecora Rojo, was studied under sprinkler irrigation system. The fertilizers applied were the conventional N-fertilizer, urea (U) applied as single dose or in three split applications (U-S), and the slow release N-fertilizers, ureaform (UF) (38% N and 20 N), osmocote (OC) with 9 or 14 months longevity and sulphur-coated urea (SCU) with either 17% or 37% dissolution rates in 7 days. These fertilizers were applied at 0 (control), 75, 125, and 175 kg/ha during the 1982–1983 season. Results indicated that at 75 kg/ha there was no significant change in the protein content. At 125 kg/ha, the protein content increased (P<0.05) with urea (applied in three split applications) and OC. At 175 kg/ha, all the fertilizers increased the protein content with the exception of urea (applied as single dose) and UF. Ash content tended to decrease with increasing levels of N, while fat and crude fiber were unaffected. All the fertilizers increased the protein yield (kg/ha), the maximum increase occurring with the slow-release N fertilizers, OC and SCU. Except UF, all the fertilizers decreased the lysine content significantly (P<0.05) in the protein moeity at 175 kg/ha level but lysine percentage in the grain was not reduced. The yield (kg/ha) of individual amino acids including lysine was increased several times at the 175 kg/ha level. P content tended to decrease while Fe and Zn increased with fertilization. Slow-release N-fertilizers, OC and SCU as well as urea (in 3 split applications) appear to have a significant positive effect on the nutritional quality of the grains of wheat variety, Yecora Rojo.     

Comparative study on the aflatoxin B1 degradation ability of rumen fluid from Holstein steers and Korean native goats

The aflatoxin B1 degrading abilities of two different ruminants were compared in this study. One set of experiments evaluated the aflatoxin B1 degradation ability of different rumen fluid donors (steers vs. goats) as well as the rumen fluid filtration method (cheese cloth filtered vs. 0.45 µm Millipore) in a 2 × 2 factorial arrangement. Additional studies examined aflatoxin B1 degradation by collecting rumen fluid at different times (0, 3, 6, 9 and 12 h) after feeding. Cannulated Holstein steers (740 ± 10 kg bw) and Korean native goats (26 ± 3 kg bw) were fed a 60% timothy and 40% commercial diet with free access to water. Rumen fluid from Korean native goats demonstrated higher (p < 0.01) aflatoxin B1 degradability than Holstein steers. However, filtration method had no significant influence on degradability. In addition, aflatoxin degradation did not depend upon rumen fluid collection time after feeding, as no significant differences were observed. Finally, a comparison of two types of diet high in roughage found aflatoxin degradability in goats was higher with timothy hay opposed to rice straw, although individual variation existed. Thus, our findings showed the aflatoxin degradability is comparatively higher in goats compared to steers.