ABSTRACT
Water stress can lead to physiological and morphological damage, affecting the growth and development of popcorn. The objective of this study was to identify the yield potential of 43 popcorn lines derived from a Latin American germplasm collection, based on agronomic and physiological traits, under full irrigation (WW) and water deficit conditions (WS), aiming to select superior germplasm. The evaluated agronomic traits included the ear length and diameter, number of grains per row (NGR) and rows per ear (NRE), grain yield (GY), popping expansion (EC), volume of expanded popcorn per hectare (VP), grain length (GL), width, and thickness. The physiological traits included the chlorophyll, anthocyanin, and flavonoid content in the leaves. The genetic variability and distinct behavior among the lines for all the agronomic traits under WW and WS conditions were observed. When comparing the water conditions, line L292 had the highest mean for the GY, and line L688 had the highest mean for the EC, highlighting them as the most drought-tolerant lines. A water deficit reduced the leaf greenness but increased the anthocyanin content as an adaptive response. The GY trait showed positive correlations with the VP, NGR, and GL under both water conditions, making the latter useful for indirect selection and thus of great interest for plant breeding targeting the simultaneous improvement of these traits.
ABSTRACT
Under conditions of soil water limitation and adequate irrigation, we conducted an investigation into the growth dynamics, gas exchange performance, and proteomic profiles of two inbred popcorn lines-L71, characterized as drought-tolerant, and L61, identified as drought-sensitive. Our goal was to uncover the mechanisms associated with tolerance to soil water limitation during the flowering. The plants were cultivated until grain filling in a substrate composed of perlite and peat within 150cm long lysimeter, subjected to two water conditions (WC): i) irrigated (WW) at lysimeter capacity (LC - 100%), and ii) water-stressed (WS). Under WS conditions, the plants gradually reached 45% of LC and were maintained at this level for 10 days. Irrespective of the WC, L71 exhibited the highest values of dry biomass in both shoot and root systems, signifying its status as the most robust genotype. The imposed water limitation led to early senescence, chlorophyll degradation, and increased anthocyanin levels, with a more pronounced impact observed in L61. Traits related to gas exchange manifested differences between the lines only under WS conditions. A total of 1838 proteins were identified, with 169 differentially accumulated proteins (DAPs) in the tolerant line and 386 DAPs in the sensitive line. Notably, differences in energy metabolism, photosynthesis, oxidative stress response, and protein synthesis pathways were identified as the key distinctions between L71 and L61. Consequently, our findings offer valuable insights into the alterations in proteomic profiles associated with the adaptation to soil water limitation in popcorn.