Influence of temperature on the fermentation of bambara groundnut (Vigna subterranea) to produce a dawadawa-type product

Bambara groundnut (Vigna subterranea) was fermented to produce a dawadawa-type product using a starter culture of Bacillus licheniformis isolated from naturally fermenting bambara groundnut beans. Fermentation was carried out at 30 and 37 °C for four days and at 45 °C for two days. The pH of the substrate decreased after 24 hours and then rose at 30 and 37 °C but remained constant at 45 °C after the initial drop. Total titratable acidity of the fermenting beans mimicked the pH values. Proximate analyses for moisture, protein and fat of the cotyledons showed an increase in all three constituent at each of the three fermentation temperatures. At the end of fermentation, total available carbohydrate was 55%, 59% and 62% of the original value at 30, 37 and 45 °C, respectively. Fermentation of bambara groundnut at 45 °C for two days is recommended as the ideal fermentation temperature and time.     

不同花生品种经济用水指标研究

研究了水分对3个花生品种(鲁花11、鲁花14号、花育16号)农艺性状及耗水特点的影响，在此基础上对各水分处理的经济效益进行了综合评价。结果表明：花生的荚果产量均随土壤相对含水量的上升呈先升后降的趋势，其中鲁花11号和花育16号在土壤相对含水量70％时荚果产量最大，而鲁花14号的荚果产量在土壤相对含水量60％最大。耗水量与水分生产率呈负相关，鲁花11的抗旱性最强，鲁花14号次之，花育16号最差。就经济效益而言，鲁花14号在土壤相对含水量为60%时经济效益最佳，而鲁花11和花育16号均在土壤含水量为70％时最佳，因此鲁花11号和花育16号的高产高效适宜土壤相对含水量为70％，而鲁花14号的为60％左右。     

Role of Testa, Cotyledons and Embryonic Axis in Seed Dormancy of Groundnut (Arachis hypogaea L.)

Experiments were carried out during winter–summer (January–June) season to understand the role of seed testa, cotyledons and embryonic axis in imparting dormancy of some groundnut cultivars belonging to different habit groups. Crop was harvested at four maturity stages; 90, 100, 110 and 121 days after emergence (DAE). After drying the pods in shade for 2 days, the germination of seeds with (GST) and without (GSW) testa in rolled germination towels and seeds, and embryonic axes (GEM) in culture media from individual plants of a cultivar was studied. Seed testa played an important role in imparting dormancy followed by the cotyledons, and embryonic axis. However, the nature of dormancy of embryonic axis appeared to be different from that of the testa and cotyledons. Results suggested that the dormancy in groundnut is regulated mainly by testa (a maternal tissue) in the Spanish type, but by cotyledons, and embryonic axis (both zygotic tissue) as well as testa in Virginia types. Thus the genetic control of seed dormancy in groundnut appears to be quantitative in nature.     

Diseases of Rubber and their Control

Abstract

Most of the major diseases of Hevea brasiliensis are of worldwide distribution (with the notable exception of South American leaf blight, against which strict quarantine regulations are enforced by rubber-growing countries outside the Americas to prevent the unauthorised import of Hevea) but their local severity and importance vary from one region to another. Root diseases are a serious problem nearly everywhere and regular rounds of inspection and treatment are essential while the trees are still young in order to prevent serious losses. The recently introduced prophylactic collar protectant dressings specific to each of the three main diseases are valuable aids to control.

Diseases of the tapping panel may prevent tapping or hinder bark regeneration; black stripe in particular (Phytophthora palmivora) can be very persistent and is often eradicated only by repeated therapeutic fungicidal treatment of the bark. Stem diseases, chiefly pink disease (Corticium salmonicolor), are important in certain areas in wet weather, and can lead to severe damage and even dieback in the absence of effective treatment.

Four major leaf diseases can have a debilitating effect on the tree. Abnormal leaf fall (Phytophthora spp.) is severe in India, causing the abscission of mature leaves during the monsoon rains; treatment necessitates the application of a pre-monsoon prophylactic copper spray. Secondary leaf fall, caused both by Oidium heveae and Colletotrichum gloeosporioides which infect the flushes of new leaves produced after the annual leaf change (wintering), varies greatly in severity according to local weather and cultivar. It can be controlled by repeated rounds of an appropriate prophylactic fungicide or, under certain conditions, by artificially hastening the onset of wintering (and thus of refoliation) by removing the old leaves with a contact herbicide. By far the most important leaf disease is South American leaf blight (Microcyclus ulei); it is largely responsible for the lack of a vigorous rubber industry in South America, the home of the rubber tree. It can only be effectively countered by the use of resistant cultivars.

The economic importance of the above diseases is discussed and current control measures described.     

Chemical,sensory and rheological properties of porridges from processed sorghum (Sorghum bicolor,bambara groundnut (Vigna subterranea L. Verdc) and sweet potato (Ipomoea batatas) flours

The chemical, sensory and rheological properties of porridges made from blends of sprouted sorghum, bambara groundnuts and fermented sweet potatoes were examined. Sorghum and bambara groundnuts were sprouted for 48 h while sweet potatoes were fermented for the same period. Blends were formulated from the processed ingredients in the ratio of 60:40:0, 57:42:1, 55:44:1 and 52:46:2 (protein basis) of sorghum, bambara groundnuts and sweet potatoes. Porridges were prepared from the composite flours and the traditional sorghum complementary food. Standard assay methods were used to evaluate the flours for nutrient composition. The porridges were also tested for sensory properties and viscosity. Processing increased the levels of most of the nutrients evaluated. Relative to the sorghum traditional complementary food, thecomposite flours had higher levels of lipids, protein, ash, crude fiber and minerals (p<0.05). The porridges from the composite flours were generally liked slightly by the panelists and were about seven times less viscous than the porridge from the traditional sorghum complementary food. Use of the composite flours, particularly the 52:46:2 blend, as a traditional complementary food should be encouraged in Nigeria especially with the increasing cost of commercial complementary foods.     

Morphological, cytological and disease resistance studies of the intersectional hybrid between Arachis hypogaea L. and A. glabrata Benth.

Arachis glabrata Benth, variety glabrata collector GK 10596 (PI276233; ICG 8176) belonging to section Rhizomatosae has resistance to rust, late leaf spot and viral diseases. A. hypogaea L. cv MK 374 (section Arachis) is susceptible to rust, late leaf spot and to the viral diseases peanut stripe, peanut mottle and peanut bud necrosis. Hybrids between A. hypogaea cv MK 374 and A. glabrata were produced after inter specific pollinations and embryo culture. The hybrids produced had morphological characters of both parents plus floral abnormalities not seen in either parent. It was possible to identify the hybrids by esterase isozyme analysis when still in culture. Cytological research showed variable chromosome association and also homeology between the genomes of A. hypogaea and A. glabrata. The hybrids inherited resistance to rust, late leaf spot, peanut bud necrosis and peanut stripe diseases from the pollen parent A. glabrata. This revised version was published online in August 2006 with corrections to the Cover Date.     

The genomes of Arachis hypogaea 2. The implications in interspecific breeding

Summary The existence of structural differentiation between genomes in section Arachis of the genus Arachis has important implications in the utilization of diploid wild species in this section as a germplasm resource. Maximum expression of desirable characters may not be achieved unless tetrasomic dose levels can be achieved. Possible breeding strategies discussed include natural and induced gene exchange between genomes and chromosome substitution which could be brought about by manipulation of ploidy level and where appropriate the use of ionizing radiation. Such strategies could be tested in the improvement of resistance to the Cercospora leafspots.Paper number 5561 of the Journal Series of the North Carolina Agricultural Experimental Station, Raleigh, NC 27650.     

Inheritance of albinism in certain interspecific and intersubspecific crosses in groundnut (Arachis hypogaea L.)

Summary A study of the several interspecific and inter-subspecific crosses indicated that albinism in groundnut is recessive and in these crosses is controlled by triplicate recessive loci.ICRISAT Paper No. JA-336     

Mature plant and tissue resistance in the groundnut-peanut bud necrosis virus system

Summary Leaves and plants of different ages of a susceptible and two resistant groundnut genotypes were mechanically inoculated with peanut bud necrosis virus, and the percentage of plants with systemic symptoms (incidence) and the incubation period were determined. The incidence decreased sharply in all three genotypes with the age of the inoculated leaves and plants. The incubation period increased with the age of leaves and plants. Apparently, only young tissue of young plants is susceptible, while mature tissue and plants are highly resistant. This mature tissue and plant resistance occurs irrespective of the susceptibility level of the genotype to peanut bud necrosis virus, however, it develops earlier in the resistant than in the susceptible genotypes.Abbreviations IP₅₀ incubation period - PBNV peanut bud necrosis virus - TSWV tomato spotted wilt virus