A Simple Phenotypic Marker for Screening Pod Shattering in Cowpea (Vigna unguiculata (L.) Walp.)
Samreen Fatima *
Stress Physiology Lab, Division of Genetics and Plant Breeding, SKUAST-Kashmir, Wadura, 193201, India.
Aaqif Zaffar
Stress Physiology Lab, Division of Genetics and Plant Breeding, SKUAST-Kashmir, Wadura, 193201, India.
Melle Sugandha
Stress Physiology Lab, Division of Genetics and Plant Breeding, SKUAST-Kashmir, Wadura, 193201, India.
Sanifa Showkat
Stress Physiology Lab, Division of Genetics and Plant Breeding, SKUAST-Kashmir, Wadura, 193201, India.
Rayan Bhat
Stress Physiology Lab, Division of Genetics and Plant Breeding, SKUAST-Kashmir, Wadura, 193201, India.
Sanjeeda Showkat
Stress Physiology Lab, Division of Genetics and Plant Breeding, SKUAST-Kashmir, Wadura, 193201, India.
Prachi Singh
Stress Physiology Lab, Division of Genetics and Plant Breeding, SKUAST-Kashmir, Wadura, 193201, India.
Asmah Khan
Stress Physiology Lab, Division of Genetics and Plant Breeding, SKUAST-Kashmir, Wadura, 193201, India.
Ifra Lateef
Stress Physiology Lab, Division of Genetics and Plant Breeding, SKUAST-Kashmir, Wadura, 193201, India.
Audil Gull
Stress Physiology Lab, Division of Genetics and Plant Breeding, SKUAST-Kashmir, Wadura, 193201, India.
Sajad Majeed Zargar
Division of Plant Biotechnology, SKUAST-Kashmir, Shalimar Campus 190025, India.
Kuldeep Tripathi
ICAR National Bureau of Plant Genetic Resources, New Delhi, 11001, India.
Asif Shikari
Stress Physiology Lab, Division of Genetics and Plant Breeding, SKUAST-Kashmir, Wadura, 193201, India.
Fehim J. Wani
Stress Physiology Lab, Division of Genetics and Plant Breeding, SKUAST-Kashmir, Wadura, 193201, India.
Parvaze Ahmad Sofi *
Stress Physiology Lab, Division of Genetics and Plant Breeding, SKUAST-Kashmir, Wadura, 193201, India.
*Author to whom correspondence should be addressed.
Abstract
Pod shattering is a major domestication-related trait and one of the principal causes of pre-harvest yield losses in cowpea (Vigna unguiculata (L.) Walp.), particularly under hot and dry conditions. Rapid and reliable identification of shattering-resistant genotypes is essential for improving breeding efficiency. The present study evaluated a national core collection of 245 diverse cowpea genotypes over three consecutive years (2023–2025) to identify a simple phenotypic marker associated with pod-shattering resistance. Genotypes were screened using a modified Random Impact Method (RIM), and pod physical traits, including pod length, pod breadth, pod thickness, pod wall weight, seed-to-pod ratio, and dorsal suture morphology, were examined for their association with shattering response. A distinct and consistent morphological marker was identified in the dorsal suture of mature pods. Shattering-resistant genotypes exhibited a single, prominent dorsal ridge positioned above the dehiscence zone, whereas susceptible genotypes consistently displayed a two-ridged dorsal suture separated by a central depression that appeared to reduce tissue integrity and facilitate pod rupture under mechanical impact. The observed marker remained stable across years and environmental conditions, indicating its reliability as a rapid visual indicator of shattering resistance. The modified RIM provided a standardised, reproducible, and cost-effective approach for evaluating pod shattering while minimising environmental variation associated with field phenotyping. The identified dorsal ridge morphology offers a simple, non-destructive, and efficient phenotypic marker for large-scale germplasm screening and the selection of resistant genotypes. This marker can accelerate breeding for pod-shattering resistance, improve yield stability, and facilitate the development of climate-resilient cowpea cultivars adapted to drought-prone environments.
Keywords: Cowpea, Pod shattering, Phenotypic marker, dorsal suture morphology, random impact method, germplasm screening, climate-resilient breeding