Drought tolerance in cultivated sunflower (Helianthus annus): on field evaluation of INTA´s association mapping population in Argentina

HEINZ, N.; MAZZALAY, A.; FILIPPI, C. V.; PANIEGO, N. B.; LIA V.V.; ALVAREZ, D.

Congreso; 20th International Sunflower Conference; 2022

International Sunflower Association

Currently sunflower production presents an important gap between actual and potential yield, being water deficit probably the most important abiotic factor limiting crop growth and yield. The objective of this work was to evaluate the behavior of drought tolerance in 159 inbred lines of the association mapping population of the National Institute of Agricultural Technology (INTA) in order to generate phenotypic data for future association mapping (AM) studies and to identify new sources of tolerance. The inbred lines were planted following a partially repeated block design with randomly distributed plots. Agroethylene was placed to prevent water entry by precipitation and to generate a moderate progressive water deficit until the end of the cycle. The irrigation condition was achieved by drip irrigation. Leaf temperature, stomatal conductance, radiation interception (fPARi), plant height, stem diameter and head diameter were recorded as descriptors of water deficit during R3-R5. After harvest, the following traits were measured: 100-seed weight, number of kernels per capitulum, oil content, seed yield and oil yield. Flowering time was recorded as a phenological trait. Under the water deficit condition, all drought tolerance descriptors presented lower absolute values with the exception of thermal time to flowering, leaf temperature and 100-seed weight which were higher. The observed differences were statistically significant in all cases except for thermal time to flowering, oil content and oil yield (p > 0.05). Random effects models revealed that the contribution of inbred lines to the overall variance was highly variable, ranging from 3.31% to 56.27%, with field trials being responsible for a large part of the variation.