Characterisation of maize landraces from Argentina at the phenotypic and biochemical levels

Abstract

In Argentina, there are about 60 maize (Zea mays ssp. mays) landraces, with two main diversity centers in the Andean and Mesopotamian-Chaco plain regions. These landraces show high genetic diversity, which makes them a vital resource to increase the gene pool of modern cultivars with the aim of adapting agriculture to climate change. Although they have been largely characterised morphologically, the comparison of their biochemical and physiological-phenological characteristics has been scarcely performed. In this work, 20 accessions of maize landraces from Argentina from the “Banco Activo de Germoplasma INTA Pergamino" were analysed in a common garden under greenhouse-controlled conditions. The average number of leaves at 30 and 62 days after germination (DAG) of the 20 accessions was 8.35 (standard deviation or SD=0.98) and 15.18 (SD=2.14), respectively. Two accessions reached 100 % of male flowering at 70 DAG, eight at 77 DAG and six at 87 DAG, while the rest did not flower. Female flowering showed desynchronization with respect to male flowering, with 4 entries bearing 100% flowering at 77 DAG, and 6 entries at 87 DAG. The average total biomass per plant was 44.65 g (SD = 30.84). In addition, various leaf biochemical variables were measured, including chlorophyll a, chlorophyll b, total chlorophyll and carotenoids, whose averages were 1583.42 µg/ml g (SD= 878.53), 424.99 µg/ml g (SD= 231.21), 2008.41 µg/ml g (SD= 1102.43) and 370.05 µg/ml g (SD= 179.13), respectively. Leaf total sugar content mean was 37.7 µg/µl g (SD= 22.34), while that of total protein was 7.47 µg/µl g (SD= 4.3). The combination of univariate and multivariate statistical analyses showed that there is significant phenotypic and metabolic variation among the accessions, with no clear grouping patterns in relation to geographical origin or grain type. These results highlight the importance of considering the distinctiveness of individual accessions in future conservation and utilisation programs.