INHERITANCE PATTERN OF YELLOW FOLIAGE COLOUR AND ACTIVITIES OF TRANSPOSABLE ELEMENT IN COWPEA Vigna unguiculata (L.) Walp

Abstract

Foliage colour may affect the photosynthetic activities of a plant and consequently yield. Differences in the green foliage colour of plants often reflect differences in chlorophyll concentration of the leaves. This study investigated the inheritance pattern of a yellow foliage mutant in cowpea. Seeds of a nuclear yellow foliage mutant and three green foliage cowpea lines were planted in plastic buckets filled with garden soil on the roof top garden of Department of crop Protection and Environmental Biology, University of Ibadan, Nigeria and crossed to produce six generations per cross comprising parents, F 1 , F 2 and BC. The various generations were and on the field at the Teaching and Research Farm of the University of Ibadan, Nigeria and data were collected on phenotypic traits. The nuclear yellow foliage mutant segregated in the ratio 3green:1yellow, thus indicating that the trait was controlled by monogenic recessive gene. Some F 2 and BC plants of the yellow foliage mutant exhibited variegation for leaf colour indicating gene instability resulting from the action of transposable element. The frequencies of reversion from the yellow to green of F 3 progenies vary widely within and between progeny rows. Of a total of 309 individual plants that were scored, 55% were variegated, 23% were green while 22% exhibited the yellow phenotype. The gene symbol yfc-3 was assigned to the recessive condition, while yfc-3 un was assigned to the unstable allele of yellow foliage.