Physiological traits involved in grazing tolerance of alfalfa genotypes

Abstract

Alfalfa [1] is one of the most largely distributed forage legume species in the world and it is used on more hectares than any other forage legume. Even so, alfalfa production in Brazil is still limited by the low persistence of this species, especially when used for grazing. Therefore, the objective of this study was to evaluate and select grazing-tolerant germplasm by evaluating genotypes based on their physiological traits. Eight alfalfa genotypes were grown in two different and simultaneous experiments. The experiment ‘A’ evaluated physiological traits: a) chlorophyll content b) sum of lateral roots and shoot and c) length of the first internode The experiment ‘B’ consisted of a jasmonate treatment, which induced remarkable effects on alfalfa roots performance. The CRAltR genotype showed the most promising results for length of the first internode 0.429 cm at the last day of evaluation (day 15). Furthermore, this genotype obtained higher rates in the evaluation of chlorophyll. E1C4AltR in addition to being selected in previous studies for grazing tolerance showed variability for decumbent habit and intermediate values for chlorophyll. The genotypes E1C4 AltR and CRAltR presented more promising results and they will be used for further field evaluations in Brazil.