Unveiling Drought-Resilient Latin American Popcorn Lines through Agronomic and Physiological Evaluation.

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.

Seeds of nonhost species as sources of toxic compounds for the cowpea weevil Callosobruchus maculatus (F.).

Cowpea weevil, Callosobruchus maculatus, is the primary pest of stored cowpea seeds. The management of this infestation currently relies on insecticides, resulting in environmental pollution and selection of insecticide-resistant pests. Consequently, research efforts are being devoted to identify natural insecticides as sustainable and environment friendly alternatives for the control of C. maculatus. In this study, we explore the toxic effects of the nonhost seeds Parkia multijuga, Copaifera langsdorffii, Ormosia arborea, Amburana cearensis, Lonchocarpus guilleminianus, Sapindus saponaria, and Myroxylon peruiferum, on the cowpea weevil C. maculatus. Notably, all nonhost seeds led to reductions between 60 and 100% in oviposition by C. maculatus females. Additionally, the larvae were unable to penetrate the nonhost seeds. Artificial seeds containing 0.05% to 10% of cotyledon flour were toxic to C. maculatus larvae. Approximately 40% of larvae that consumed seeds containing 0.05% of O. arborea failed to develop, in contrast to control larvae. Proteomic analysis of A. cearensis and O. arborea seeds identify revealed a total of 371 proteins. From those, 237 are present in both seeds, 91 were exclusive to O. arborea seeds, and 43 were specific to A. cearensis seeds. Some of these proteins are related to defense, such as proteins containing the cupin domain and 11S seed storage protein. The in silico docking of cupin domain-containing proteins and 11S storage protein with N-acetylglucosamine (NAG)4 showed negative values of affinity energy, indicating spontaneous binding. These results showed that nonhost seeds have natural insecticide compounds with potential to control C. maculatus infestation.

Exploring the Potential of Heterosis to Improve Nitrogen Use Efficiency in Popcorn Plants.

Nitrogen is crucial for plant growth and development, and improving nitrogen use efficiency (NUE) is a viable strategy for reducing dependence on nitrogen inputs and promoting sustainability. While the benefits of heterosis in corn are well known, the physiological mechanisms underlying this phenomenon in popcorn are less understood. We aimed to investigate the effects of heterosis on growth and physiological traits in four popcorn lines and their hybrids under two contrasting nitrogen conditions. We evaluated morpho-agronomic and physiological traits such as leaf pigments, the maximum photochemical efficiency of PSII, and leaf gas exchange. Components associated with NUE were also evaluated. N deprivation caused reductions of up to 65% in terms of plant architecture, 37% in terms of leaf pigments, and 42% in terms of photosynthesis-related traits. Heterosis had significant effects on growth traits, NUE, and foliar pigments, particularly under low soil nitrogen conditions. N-utilization efficiency was found to be the mechanism favoring superior hybrid performance for NUE. Non-additive genetic effects were predominant in controlling the studied traits, indicating that exploring heterosis is the most effective strategy for obtaining superior hybrids to promote NUE. The findings are relevant and beneficial for agro farmers seeking sustainable agricultural practices and improved crop productivity through the optimization of nitrogen utilization.