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Agronomic Aspects of Normal and Abnormal Root Formation in Peanuts (Arachis hypogaea L.)

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Abstract

Peanut (Arachis hypogaea L.) research in Ontario, Canada has focused on the problems inherent in growing a crop in an area where it had previously not been grown. It had been observed that a significant percentage of germinating seeds developed abnormal root systems. Many of these abnormal seedlings did not emerge; others emerged but failed to produce vigorous plants.

Four peanut cultivars, each from two distinct sources, commercial and hand-harvested seeds were compared on the basis of pod yield, plant stand, and percentage of plants with normal root systems. A normal root system was designated as one which had a long straight tap root with many laterals. Among all cultivars, pod yield, and plant stand from hand-harvested seed exceeded that of commercial seed. In addition, the percentage of plants with normal root systems was greater for hand-harvested seed than for commercial seed with two of the cultivars.

Field grown plants of three peanut genotypes were examined to determine the relative percentages of plants with normal or abnormal root systems. An abnormal root system was classified as having a curvature of the hypocotyl or the hypocotyl and tap root or no main tap root. High percentages (50–60%) of plants with abnormal root systems were found for two genotypes and for each of the three genotypes it was determined that an abnormal plant was capable of producing approximately 50% as many pods as a normal plant.

Four sources of seeds were collected for each of the three genotypes: (a) normal-rooted plants, (b) abnormally-rooted plants, (c) a random selection of plants, and (d) a random selection of plants, combine-harvested. The seeds were grown in a growth cabinet study and in two field trials. In all cases, the data were consistent in that selection for normal-rooted plants did not increase the percentage of normal-rooted plants over the random selection or the abnormal selection in the following generation. Combine-harvesting caused a dramatic reduction in the percentage of plants with normal roots. In two genotypes this reduction led to a significant yield reduction when compared to the hand-harvested selections. Seed from a commercial seed lot for one of the genotypes produced a very low percentage of plants with normal roots, which also resulted in a yield reduction.

The overall results demonstrated that the use of high quality seed was an extremely important facet of peanut production in this environment and that additional research in the area of seed quality is justified.

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Keywords: Arachis hypogaea, seed quality, Seed Damage, Normal and Abnormal Roots

How to Cite: Ablett, G. , Roy, R. & Tanner, J. (1981) “Agronomic Aspects of Normal and Abnormal Root Formation in Peanuts (Arachis hypogaea L.)”, Peanut Science. 8(1). doi: https://doi.org/10.3146/i0095-3679-8-1-7