Morphological features and inheritance of Foliaceous Stipules of primary leaves in cowpea (Vigna unguiculata).
OBJECTIVE
The presence of connate foliaceous stipules of primary leaves and their inheritance in cowpea (Vigna unguiculata) genotype EC394736 is reported for the first time.


METHODS
The development of foliaceous stipules (FS) and their persistence were examined throughout the growth and developmental stages of the plants of the genotype EC394736. The shape, size, colour, texture and other parameters were examined in the field during the period 15-50 d after sowing. The area of FS was measured using image analysis software. The inheritance of FS was studied by making a cross between the genotype EC394763 with rudimentary stipules (RS) and the genotype EC394736, which has connate foliaceous stipules of primary leaves. The presence or absence of FS in plants of the F1, F2 and F3 generations was recorded.


RESULTS
The stipules developed along with the primary leaves in the genotype EC394736. One stipule of each primary leaf fused with the adjacent stipule of the other primary leaf forming a foliaceous structure. These stipules persisted on the plants for >50 d, even after the primary leaves had withered off. The F1 plants showed an absence of FS indicating the rudimentary stipules to be dominant over foliaceous stipules. The F2 segregation into 15 (RS) : 1 (FS) indicated that duplicate recessive genes controlled the presence of the FS. This was confirmed from the segregation pattern in the F3 generation.


CONCLUSIONS
The presence of FS is a unique feature in cowpea genotype EC394736 and duplicate recessive genes govern it. The FS can be used as a morphological marker for identification of cowpea varieties.
Nuclear Agriculture and Biotechnology Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085, India. rnpandey@apsara.barc.ernet.in
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Pandey
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Dhanasekar
D003433:Crosses, Genetic; D007887:Fabaceae / Q000235:genetics* / Q000254:growth & development; D005838:Genotype; D018515:Plant Leaves / Q000235:genetics* / Q000254:growth & development