GGE biplot analysis for yield performance and stability assessment of carrot genotypes (Daucus carota L.) under multi-environment trials (METs)

The stability of yield and contributing traits is a very important factor for long-term development and sustainability of cultivars. The genotype x environment (G x E) interaction on the yield stability in twenty-eight genotypes of carrot was studied under eight environments E1-E8 (different sowing dates) over the two years (2019-20 and 2020-21) at Vegetable Research Farm, Punjab Agricultural University, Ludhiana. The experiment was laid out in randomized complete block design with three replications under each environment. At each harvest, data was recorded for root yield (q acre(-1)), marketable yield (q acre(-1)), root length (cm), root weight (g), root-shoot ratio, root diameter (cm), core diameter (cm), shoot length (cm), shoot weight (g) and number of leaves plant(-1). The data was analyzed with ANOVA, mixed models, BLUPs, GGE biplot and multi stability index for stability statistics. For all the traits, pooled analysis of variance revealed highly significant (p < 0.01) variations between genotypes, environments and genotype by environment (G x E interaction). The mean vs. stability view of GGE biplots revealed that genotype PC-171 (G6) performed better in the months of August and September of both the years (E1, E2, E5 and E6). PC-160 (G3) followed by Cartvar-2 (G25) performed better in the month of October (E3 and E7) for the root yield parameter. Mean across the environments and BLUP values of genotypes for all the traits showed similar results. Hence, GGE biplot graphically explained the interrelationships between the tested environments and genotypes, classified genotypes into three categories early, mid or late season based on their mean performance and stability in the given growing environment.