Phenotyping for Groundnut (Arachis hypogaea L.) Improvement

Abstract

Groundnut (Arachis hypogaea L.) is grown world over for oil and food uses. It is a self-pollinated crop with low genetic diversity. The origin of the crop from single hybridization event followed by chromosome doubling as well as cross ing barriers of cultivated species with wild species due to ploidy differences ren dered the crop with narrow genetic variability. Developing new varieties with increased yield potential and resistance to biotic and abiotic stresses that meet the needs of the growers, processors and consumers is the primary objective of ground nut breeding. In this chapter, we discuss about phenotyping tools used in groundnut improvement programs for various targeted traits. Both field and laboratory tools are described to screen for resistance to diseases caused by fungi, bacteria, virus and nematodes. Phenotyping based on Cumulative Thermal Time (CTT) is used to select for early maturity. Phenotyping for complex traits can be challenging. Either empirical approach that involves measuring the yield under imposed drought stress or salinity conditions or trait based approach using surrogates or a combination of both are used for phenotyping abiotic stresses. Phenotyping for Aspergillus con tamination needs improvement to derive reliable and reproducible results. Estimation of quality and nutritional parameters generally involves use of destructive and labo rious chemical or physical procedures. Near infrared reflectance spectroscopy (NIRS), a robust and non-destructive method is gaining popularity for estimation of oil, protein, carbohydrate and fatty acid contents. Methods for estimating oil, pro tein, sugar and micronutrient concentrations and fatty acid composition of seeds and haulm quality traits are described.

Comparative Evaluation of Agronomic Performance of Selected Landraces And Improved Groundnuts Cultivars In Central Uganda

“…As groundnut is grown in predominantly semi-arid regions characterized by erratic rainfall and on predominantly loose sandy loam soils, drought is often a recurring production constraint. This situation also coincides with the climate change phenomenon which projects disturbances such as a decrease in the lengths of the rainy seasons especially in semi-arid tropics (SAT) where most groundnuts are grown (Pasupuleti and Nigam 2013). In addition, drought has signi cant implications on groundnut quality which undermines the value of groundnut products on local, regional and international markets.…”

Pérennisation par modélisation résiliente dans la culture de l’arachide (<i>Arachis hypogaea L.</i>) au Cameroun (Synthèse bibliographique)

“…Connaître ou identifier les principales pathologies de l'arachide serait une bonne mesure préventive, mais aussi préhensive dans la lutte contre les pathologies, car elle est sous l'influence de plus de quarante pathologies (Middleton et al, 1994). La principale maladie de l'arachide est la cercosporiose (Shokes & Culbreath, 1997), qui est une maladie cryptogamique causant des pertes de rendements allant jusqu'à 70 % (Pasupuleti et al, 2013 ;Zongo, 2013), et parfois 100 % comme en Afrique du Sud (Pretorius, 2006). Cette pathologie attaque principalement les feuilles et toutes les parties vertes de la plante (Iroumé et al, 1991 ;Iroumé, 2004).…”

Utilization of Plant Genetic Resources of Bambara Groundnut Conserved Ex Situ and Genetic Diversification of Its Primary Genepool for Semi-Arid Production

“…targeted on seeds, plant organs, whole plantlets, and pollen to alter traits in an otherwise elite or adapted variety [72]. Mutation breeding through gamma radiation and chemicals has successfully led to the development of 72 groundnut cultivars in highly cleistogamous species, such as groundnut (Arachis hypogea) [73]. In bambara, gamma radiation mutagenesis contributed to a broadened variability of yield components, such as plant height, branches per plant, pod yield, and seed weight [74].…”

“…Breeding for drought tolerance can be achieved through empirical (selecting directly for yield) or physiological breeding (selection for secondary traits). Yield is a primary trait used for selecting for drought tolerance, thus the empirical breeding approach emphasizes breeding for drought tolerance by directly aiming for yield and yield components [73]. It is perceived that this approach likely confers a two-fold advantage, whereby the cultivars that produce higher yields under optimal conditions will produce higher yields during seasons of above-normal rainfall, whilst during periods of low moisture, they are likely to produce fairly higher yields [84].…”