Bridging conservation and breeding: collection and characterization of Nepalese garlic (Allium sativum L.) landraces

Abstract

Garlic (Allium sativum L.) is a major horticultural crop in Nepal, but breeding efforts are constrained due to limited information on phenotypic traits among native landraces. Seventy garlic landraces, including a local check (NGRV0565), collected from 29 districts of Nepal, were characterized and evaluated at the research field of the National Agriculture Genetic Resources Centre from November 2023 to May 2024 using an augmented block design. Agromorphological traits, including 18 quantitative and 15 qualitative traits, were recorded following the standard descriptors of the International Plant Genetic Resources Institute. Shannon-Weaver diversity indices revealed a high diversity index for bulb skin thickness, neck type, foliage attitude, clove anthocyanin, and all quantitative traits. The first three principal components accounted for 76.51% of the total variation, with yield, bulb size, and plant biomass characteristics being the most important factors. The cluster dendrogram grouped garlic landraces into four clusters. Correlation and path analyses identified biomass yield, fresh plant weight, and bulb weight as the primary determinants of bulb yield, collectively explaining 95% of its phenotypic variation. Landrace NGRV0573 (18.98t/ha) was identified as the most promising based on yield, while NGRV0571 and NGRV0572 (141 days) were identified as early-maturing landraces. Furthermore, these landraces require molecular and multi-environment evaluations to refine selection and enhance garlic breeding efforts.