GENETIC DIVERSITY AND AGRONOMIC PERFORMANCE OF EXOTIC SWEET CORN (ZEA MAYS L. SACCHARATA) GERMPLASM UNDER PAKISTAN’S AGRO-CLIMATIC CONDITIONS

Abstract

Background: Sweet corn (Zea mays L. saccharata) is a nutritionally rich maize type valued for its sweetness and global market demand. In Pakistan, limited research has focused on evaluating exotic germplasm for yield, stress tolerance, and adaptability, despite its potential to improve productivity and diversify cropping systems. Understanding genetic variability and heritability among key agronomic traits is fundamental for developing superior hybrids suited to local environments.

Objective: The study aimed to evaluate the genetic diversity, heritability, and inter-trait associations among exotic sweet corn genotypes under Pakistan’s agro-climatic conditions, to identify superior parental combinations for breeding high-yielding hybrids.

Methods: Four exotic inbred lines (YSC-811, WSC-602, WSC-99, WSC-01) and their eleven F₁ hybrids were evaluated in a randomized complete block design with three replications at the University of Agriculture, Faisalabad. Morphological and yield-related traits were recorded, including plant height, tassel length, cob weight, grain weight, and shelling percentage. Data were analyzed using ANOVA, correlation, and multivariate techniques (PCA and cluster analysis). Heritability and genetic coefficients of variation were estimated to determine the genetic control of traits.

Results: Significant variation was observed among genotypes for yield and yield-contributing traits (p < 0.001). The hybrid YSC-811 × WSC-01 exhibited the highest cob weight (288.8 g) and grain weight (79.1 g), while WSC-602 displayed superior shelling efficiency (54.2 %). High heritability was found for cob weight (83.6 %), shelling percentage (83.1 %), and number of kernel rows per cob (78.3 %), suggesting strong additive gene action. Positive correlations between leaf traits and yield attributes (r = 0.71–0.92) indicated their potential as indirect selection indices. PCA revealed that the first two components accounted for 65.8 % of total variability, confirming distinct genotype groupings.

Conclusion: The study demonstrated broad genetic diversity and identified YSC-811 × WSC-01 as a superior cross for yield improvement. The findings emphasize the potential of exotic germplasm for breeding resilient, high-yielding sweet corn adapted to Pakistan’s agro-ecologies. Future efforts should integrate molecular tools and multi-environment testing to enhance selection precision and cultivar stability.