Resumo

LUNA-GUERRERO, Milton Javier  e  LOPEZ-CASTANEDA, Cándido. Genetic variability in aerial biomass and its components in alfalfa under irrigation and drought. Rev. mex. de cienc. pecuarias [online]. 2023, vol.14, n.1, pp.39-60.  Epub 24-Mar-2023. ISSN 2448-6698.  https://doi.org/10.22319/rmcp.v14i1.6129.

Drought decreases the yield of aerial biomass (BM) and its components, and the quality of forage in alfalfa. The genetic variation in BM and its components was studied in 10 varieties of alfalfa under irrigation (I) and drought (D) in a greenhouse. A randomized complete block experimental design was used, with four repetitions in I and four in D. The experimental unit was an individual plant in a PVC pipe. Sowing was carried out on March 15, 2017, and transplanting in the pipes, 20 days after sowing. The fertilization dose 60-140-00 was applied at 44, 240 and 420 dat (days after transplanting). D reduced (P≤0.01) BM, leaf dry matter yield (LDMY), number of stems (NS) and radiation use efficiency (RUE). The plants in D did not recover their productive capacity after experiencing the water deficit, even after the recovery irrigation. D also decreased (P≤0.01) the phenotypic variance for BM and its components; the additive variance was greater (P≤0.01) than the dominance variance for all traits in I and D. The BM, L:S ratio, plant height (PH), NS and RUE had higher (P≤0.01) heritability in I and D. The Genex, Atlixco, Júpiter and Milenia varieties were the most productive (P≤0.01) in D and could be used for forage production in water-scarce areas or as parental lines for forage yield improvement in selection programs.

Palavras-chave : Greenhouse; Heritability; Principal component analysis; Variance components.

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