Effect of irrigation on reproductive efficiency of bunch and spreading types of groundnut (Arachis hypogaea L.)

Groundnuts are mostly grown during the rainy season (kharif) in India. Most of the cultivation is without irrigation. Consequently the crop experiences water deficits of different intensities and durations, depending upon the rainfall distribution. Yields are poor under such conditions. In other leguminous species irrigation at flowering usually improves yield, if the pod development period coincides with a break in rainfall or water deficit (Khanna-Chopra, Koundal & Sinha, 1980). Thus, an understanding of reproductive behaviour and reproductive efficiency could be helpful in adjusting planting to coincide with favourable agroclimatic conditions. Alternatively, this understanding could help in scheduling irrigation

Growth and production of groundnut

The groundnut or peanut is one of the important legume crops of tropical and semiarid tropical countries, where it provides a major source of edible oil and vegetable protein. Groundnut kernels contain 47-53% oil and 25-36% protein. The crop is cultivated between 40ºN to 40ºS of the equator. Groundnut is a self pollinated crop whereby flowers are produced above ground and, after fertilization, pegs move towards the soil, and seed-containing pods are formed and developed underneath the soil. The productivity of groundnuts varies from 3500 kg/ha in the United States of America to 2500 kg/ha in South America, 1600 kg/ha in Asia, and less than 800 kg/ha in Africa. This is due mainly to various abiotic and biotic constraints. Abiotic stresses of prime importance include temperature extremes, drought stress, soil factors such as alkalinity, poor soil fertility and nutrient deficiencies. Groundnuts grow best in light textured sandy loam soils with neutral pH. Optimum temperature for their growth and development ranges from 28 to 30 ºC; the crop requires about 500-600 mm of well distributed rainfall. The main yield limiting factors in semiarid regions are drought and high temperature stress. The stages of reproductive development prior to flowering, at flowering and at early pod development, are particularly sensitive to these constraints. Apart from N, P and K, other nutrient deficiencies causing significant yield losses are Ca, Fe and B. Biotic stresses mainly include pests, diseases and weeds. Among insects pests pod borers, aphids and mites are of importance. The most important diseases are leaf spots, rusts and the toxin-producing fungus Aspergillus

Sources of Variation in Shelling Percentage in Peanut Germplasm and Crop Improvement for Calcium Deficiency-Prone Soils

Calcium (Ca) deficiency causes peanut pegs and pods to abort, resulting in decreased shelling percentages and yields. Environmental factors influencing calcium availability include soil Ca content and soil moisture. Genetic attributes that influence the sensitivity of cultivars to soil Ca supply include pod size, soil volume per pod (varied by plant growth habit), and pod wall attributes. Where Ca fertilization is not possible, genetic solutions to Ca deficiency are important, and breeders need information on the relative importance of these attributes. The objective of this research was to quantify the relative importance of these three sources of variation. Data from three trials were used to evaluate the relative importance of these attributes. The trials, sited on Ca-deficient alfisols, used between four and 12 germplasm lines with varied Ca sensitivity- determining attributes. Lines differed in growth habit (spreading or bunch), pod volume, pod yield, shelling percentage, and seed yield. The trial treatments and environments (sites and seasons) also varied Ca supply through soil type, fertilization, and water supply. Assuming that Ca supply has little impact on crop growth rates (CGR), a physiological model was used to set aside the contributions of CGR to yield differences between treatments. The three trials were analyzed separately and then combined for further regression analysis by defining each site and treatment combination as an environment. Within trials, variations in shelling percentage accounted for up to half the variations in seed yield between lines. In the combined analysis, easily selected attributes—pod volume (58% of germplasm sums of squares) and plant habit (8%) and their interaction (14%)—accounted for much of the variation in shelling percentage. The interaction was due to shelling percentage being less influenced by pod volume in spreading than in the bunch types. Thus, in Ca-limiting situations, the spreading growth habit allowed larger seeded peanuts to be grown than the bunch growth habit because of the greater pod dispersal of this type. Assuming that the lines tested typified peanuts for their relation between attributes and Ca deficiency-based shelling percentage variations, breeders should place the greatest emphasis on small pod size to decrease peanut sensitivity to Ca deficiency. Increased soil available to each pod by pod dispersal decreases the need for small pods to decrease sensitivity to Ca-deficient soil

Groundnut at a glance, pp.121

This book is written in a format of a ready reckoner for quick consultation by the user. It contains all the essential details of different aspects of groundnut improvement and production. The information contained herein is extracted from various formal and informal publications on groundnut. These sources are gratefully acknowledged. For more details and in-depth information, the reader is advised to consult additional literature

Modeling growth and yield of groundnut

Crop simulation models have much potential for assisting in agrotechnology transfer, crop management decision-making, climatic assessment, and in the synthesis of research results. For these reasons, it is important to continue to develop and improve models for predicting the growth and yield of groundnut (Arachis hypogaea). In this paper, we briefly review approaches for modeling growth and yield of groundnut. Then we illustrate major areas of improvement in the PNUTGRO crop growth model after evaluating PNUTGRO Vi.02 versus additional data sets from Florida and India. New areas of improvement include: 1) addition of a hedgerow photosynthesis submodel to improve response to row spacing, sowing density, and growth habit; 2) addition of the Pen mall equation to incorporate vapor pressure deficit and windspeed to estimate evapotranspiration for arid regions; 3) modification oJfunctions for prediction of crop del'elopment; and 4) modification of the effects of stress environments such as high temperature and vapor pressure deficit on partitioning

Physiological Basis for Yield Advantage in a Sorghum/Groundnut Intercrop Exposed to Drought.* 2. Plant Temperature, Water Status, and Components of Yield

In a replacement series intercrop of two rows of groundnuts cv. Kadiri 3 alternating with one row of sorghum hybrid CSH-8, increases in grain and filled-pod wt/plant due to intercropping were large, especially in droughted stands. For sorghum, grain yields were 38% and 93% higher per unit row in the irrigated and drought treatments, resp., while intercropped groundnuts produced 81% more filled-pod wt per unit row than did sole stands during drought. Harvest index was larger for both species in the intercrops, by 8% and 33% in sorghum, and by 12% and 68% in groundnuts in irrigated and drought treatments, resp. In groundnuts, harvest index was increased in the irrigated intercrop because individual pods were heavier, whereas the intercrop subjected to drought produced twice as many pods per plant in comparison with the sole crop. There were large differences in plant temp. and water status between irrigated and drought stands throughout the post-rainy season, but mean differences between sole crops and intercrops within each water regime were small. Shading of groundnuts by sorghum in the intercrop ameliorated to some extent the effects of high temp. and water stress, especially in the droughted stands. This was particularly important during peg production. It is suggested that less damage to flowers in the drought intercrop resulted in more pegs forming pods than in the sole crop, leading to the observed advantage in harvest index in groundnut

International Arachis Newsletter (IAN) No - 13

International Arachis Newslette

Quantifying the effects of high temperature and water stress in groundnut (Arachis hypogaea L.)

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