SEED MORPHOMETRY AND DIGITAL CHROMOTYPING OF AN HEIRLOOM COWPEA LANDRACE FROM A MESOHALINE FLOODPLAIN AGROECOSYSTEM, GOA, INDIA

Vigna unguiculata (L.) Walp. cv. landrace 'Alsande of Revoda' (AOR), cultivated by marginal farmers on the mesohaline tidal floodplain of the Chapora estuary, Bardez Taluka, North Goa, India, was subjected to comprehensive seed morphometry and digital chromotyping using the Leizersoft Image Color Summarizer (ICS) SDK33. A bulk lot of approximately 1,100 seeds and a random subsample of 100 seeds were independently analysed. The bulk lot resolved into 12 colour groups and 88 named colour entries; the 100-seed subsample into 15 colour groups and 74 entries. The dominant chromotypic group was Orange And Brown in both samples (68.94% bulk; 80.84% subsample). Weighted chromometric parameters: bulk lot CIE L*=57.28, a*=+16.65, b*=+30.93, Chroma C*=35.13, hue h=61.70 degrees; subsample CIE L*=62.75, b*=+35.06, h=70.70 degrees. Shannon chromatic diversity H=3.29 (bulk; 88 colour names; Pielou J=0.734); 45.5% of bulk variants were rare. The 100-seed weight was 21.63 g (mean individual mass 216.30 plus or minus 52.07 mg; CV=24.07%; modal class 200-249 mg, 45.0% of seeds). Bulk density was 0.8168 g per cm3; true particle density 1.317 g per cm3; mean seed biovolume 164.2 mm3. Calibrated image morphometry (23.08 px/mm) yielded width W=6.98 plus or minus 0.78 mm and thickness T=4.99 plus or minus 0.51 mm; length L=9.00 mm was back-calculated from biovolume, confirmed self-consistent to within 0.4%. Sphericity psi=0.755; shape index W/L=0.776 (kidney-oval). Three-way convergence of chromotypic (~45%), biomass (45.0% medium weight class 200-249 mg), and morphometric (82% medium W class) measurements independently identifies a primary AOR morphotype at approximately 45% population frequency. A 100-seed weight 144% above the ICRISAT improved-variety midpoint, combined with mesohaline floodplain provenance and zero-irrigation cultivation, supports the hypothesis that positive selection for large, high-reserve seeds has driven phenotypic differentiation in this stress-adapted landrace.