Variation in transpiration efficiency and its related traits in a groundnut (Arachis hypogaea L.) mapping population

Transpiration efficiency (TE) has been recognized as an important source of yield variation under drought stress in groundnut. Here the variation for TE is evaluated in a set of 318 recombinant inbred lines (RILs) of groundnut at F₈ generation, derived from a cross between a high TE (ICGV 86031) and a low TE (TAG 24) parent, and the value of specific leaf area (SLA), SPAD chlorophyll meter readings (SCMR) and carbon isotope discrimination (Δ¹³C) as surrogates of TE are measured. Transpiration efficiency was measured gravimetrically in the 318 RILs and parents under progressive soil drying in a pot culture in two post-rainy seasons. Large and consistent variation for TE existed among the RILs across years. The overall distribution of TE among the RILs indicated that TE was governed by dominant and additive genes. Surrogates SLA and SCMR, were measured prior, during and after completion of the drought period, whereas Δ¹³C was measured on the dried tissue after harvest. Transpiration efficiency was negatively associated with SLA after the completion of stress treatment (r² = 0.15) and Δ¹³C in leaves (r² = 0.13) and positively associated with SCMR during stress (r² = 0.17). These associations, all fairly weak, were significant only in 2004. None of these relationships was found in 2005. Although the heritability of SCMR during 2005 was relatively higher than that of TE, and although SCMR has previously been used to identify contrasting germplasm for TE, the stress-dependence of the relationship with TE, and the poor regression coefficients (r²) with that RIL population, do not confer that these surrogates are adequately robust enough in that population. Though more time consuming, a direct gravimetric evaluation for TE appeared to be more reliable.     

Integrated pest management in groundnut (Arachis hypogaea L.) in India

A large number of pests are associated with groundnut but not all are economically important. The distribution of, losses and damage caused by groundnut pests are discussed, along with a variety of control measures and methods for their integration for effective pest management. Disease resistant/tolerant varieties, including Girnar 1, ALR 1, ICGV 87160, ICGV 86590, DH 8, TG 3, MH 16, ICGS 37 and TAG 24 from India have been released for general cultivation and could be used in integrated pest management (IPM) programmes. A large number of advanced breeding lines possessing resistance to major diseases and insect pests have been identified. Biocontrol agents have been used successfully for insect and disease control. Intercrops such as pearlmillet and soybean suppress thrips, jassids and leaf miner; castor suppresses jassids and Spodoptera, and pigeonpea suppress early leaf spot, late leaf spot and rust. These plants act as traps or barriers for reducing pest incidence. The use of pheromone traps for gram pod borers, tobacco caterpillars and leaf miners, and the use of neem products against major insect pests and diseases, are novel approaches that may reduce the cost of groundnut production. If pest control measures are integrated in an optimum proportion and pest surveillance activity is strengthened further, maximum returns could be realized     

Peanut variety response to postemergence applications of carfentrazone-ethyl and pyraflufen-ethyl

Field experiments were conducted in the south Texas and Texas High Plains area in 2005 and 2006 to evaluate peanut variety tolerance to carfentrazone-ethyl and pyraflufen-ethyl. Lactofen was used as the standard. Carfentrazone-ethyl at 0.03 and 0.04 kg ai/ha, pyraflufen-ethyl at 0.003 and 0.004 kg ai/ha, and lactofen at 0.22 kg ai/ha were applied 35 days after planting (DAP) in south Texas and 51–56 DAP in the High Plains area in weed-free plots. Peanut cultivars selected for evaluation were those normally used in each area. In south Texas, Tamrun 96, Tamrun OL 01, and Tamrun OL 02 were evaluated while in the High Plains area, Flavor Runner 458, GP-1, and Tamrun OL 02 were evaluated. No peanut cultivar by herbicide interaction was observed in south Texas but an interaction did occur in the High Plains. In south Texas, peanut stunting was 10% or less with both herbicides and rates. In 2005, carfentrazone-ethyl at 0.04 kg/ha resulted in a yield reduction when compared with the untreated check while in 2006 both rates of carfentrazone-ethyl and the high rate of pyraflufen-ethyl reduced yield compared to the untreated check. No grade differences were noted among herbicide treatments. In the High Plains area, the high dose of both carfentrazone-ethyl and pyraflufen-ethyl caused the greatest peanut injury (at least 25%) compared with lactofen (6% or less). In 2005, the high dose of pyraflufen-ethyl and lactofen reduced yield compared with the untreated check while in 2006 both carfentrazone-ethyl and pyraflufen-ethyl reduced yield compared with the untreated check.     

Differential Growth, Nodulation and Nitrogen Fixation Efficiency of Groundnut Cultivars Inoculated with Different Rhizobium Strains

Growth, nodulation and nitrogen (N) fixation efficiency of Banki (Local) and ICGS-44 (exotic) varieties of groundnut was significantly ( P < 0.05) improved by their inoculation either with NC-92 or Rudy Patric (R.P.) strains of rhizobium. Nodules did not form without inoculation in plants growing in sterilized sand. Inoculation with R.P. strain of rhizobium resulted in greater shoot growth, N content in shoot and number and weight of nodules in groundnut varieties. The R.P. inoculant increased agronomic efficiency by 112.5 % in Banki and 100 % in ICGS-44 variety of groundnut. Improvement in N fixation efficiency by inoculation with R.P. inoculant was 334 and 286% in Banki and ICGS-44 variety, respectively. However, Physiological efficiency was maximum in Banki variety when inoculated with NC-92 strain of rhizobium.     

花生抗旱机制的研究进展

花生的抗旱性机制包括利用生育期的变化逃避干旱，利用形态性状的改变和器官结构及生化物质的变化抵御（抗）干旱。不同的花生品种中可能存在不同的抗旱性机制。     

地膜残留土壤对花生生育影响的研究

残膜片存留在土壤中,随存留量大小,对花生的生长与发育均产生一定影响。尤以构成产量因素的单株结果数和单株生产力的影响较大。同时,对土壤理化性状和土壤微生物消长,以及对根系发育和根活性也产生不同程度的影响,残膜片在土壤中分布角度,以180°时影响为最明显。     

长江中下游地区花生品种更替中产量及有关性状演变的初探

对长江中下游地区花生品种更替中产量及有关的２２个性状进行了相关性分析。结果表明，产量与单株有效果数、饱果数、百果重、主茎青叶数、叶面积指数、生物产量和收获指数等性状遗传相关均达正向极显著，而与株高呈极显著负相关。经分析表明，近期推广品种比地方品种增产，在于主要经济性状的综合改良和收获指数的提高由（０．３３提高到０．４６）。说明高产品种不但生物产量较高，且表明向荚果转化的物质也多。其次．主茎第六节以上的长度得到控制。避兔植株体过旺生长，更能发挥品种的增产潜力。     

花生叶形的遗传属性和配合力分析

本文通过双列杂交对花生叶片形状的遗传属性及配合力进行了分析。结果表明花生窄叶性状受显性基因控制,F_2代窄叶与宽叶的分离符合一对基因遗传(3:1)的分离比例。在不含典型窄叶亲本的组合中,叶片宽度存在一定的杂种优势,但一般配合力的效应大于特殊配合力效应,说明叶形指数主要受加性基因控制,遗传力较高。     

Effect of Solution pH and Calcium Concentration on Germination and Early Growth of Groundnut

Abstract

Most investigations on the effect of acid soil on legumes have focused on growth, nodulation, nitrogen fixation, and mineral nutrient uptake. Very little attention has been given to the effects of H⁺ toxicity per se and calcium (Ca) deficiency per se on germination and seedling survival of legumes, particularly groundnut (Arachis hypogaea L.). This paper reports the effects of solution pH and external Ca on seed germination, seedling survival, and growth of groundnut cv. Falcon in sand culture. The treatments consisted of solution pH values ranging from 3.0 to 6.0 in Experiments 1 and 2, and a factorial combination of pH (3.5, 4.5, and 5.5) and Ca (0, 0.5, 1.0, 1.5, and 2.0 mM) in Experiments 3 and 4. The percentage of groundnut kernels that germinated was little affected by solution pH, and ranged from 86% at pH 3.0 to 92% at pH 6.0. By contrast, seedling survival was more sensitive to pH, with only 51% surviving at pH 3.0 compared with 85% and 92% at pH 5.0 and 6.0, respectively. Increasing the solution Ca concentration diminished the adverse effects of low pH on germination and seedling survival. Total root length increased 425‐fold as the pH was increased from 3.0 to 6.0. Increasing the Ca concentration from 0 to 2.0 mM Ca increased root length by 140% and total root surface area by 95%. Lateral root formation was retarded by the combination of low Ca and low pH. Shoot and root dry mass increased with increasing solution pH and Ca concentration. Results of this study indicate that low pH per se did not impact on germination of groundnut, but significantly reduced seedling survival and early growth. The adverse effects of low pH on seedling growth of groundnut were alleviated by high solution Ca concentrations.