Genetic diversity of Macroptilium accessions considering the increase in air temperature

Climate changes can influence the genetic diversity of forage plants, which may contribute to the improvement and development of new species. Therefore, this research aimed to evaluate the influence of temperature increase on the genetic diversity of Macroptilium accessions based on morphoagronomic descriptors. The experiment was carried out in a growth chamber in a 2×16 factorial arrangement (temperature regimes x Macroptilium accessions), with the temperatures consisting of T1 (20­26­33 °C) and T2 (24.8­30.8­37.8 °C) and 16 accessions. Eleven morphoagronomic descriptors allowed estimating the diversity among accessions. The measurements of genetic dissimilarity enabled us to observe the genetic distance between the studied materials, standing out the accessions T1.M3 and T2.S4 as the most divergent (446.01). The morphoagronomic descriptors percentage of leaves and stem diameter were the most efficient for estimating the diversity between access. Genetic variability points to the adaptation of Macroptilium accessions in the climate change scenario. The accessions more divergent can be explored in genetic breeding programs for the species aiming at the expansion of genetic variability as an adaptation mechanism to heat stress.

Potential of parents and hybrids experimental of the yellow melon / Potencial de parentais e híbridos experimentais de melão amarelo

ABSTRACT: Melon or muskmelon (Cucumis melo L.) is of considerable economic importance in Brazil. Nearly all the cultivars currently grown are hybrids. Heterosis has been used to advantage in the melon plant, and the use of uniform hybrids is one of the reasons for successful cultivation. The aim of the present study was to evaluate the agronomic potential of yellow melon lines and hybrids. An experiment was conducted in randomized blocks with three replications to evaluate 24 hybrids generated by crosses among three elite lines used as female parents (AF-01, AF-02, and AF-03) and eight lines used as male parents (LAM-01, LAM-02, LAM-03, LAM-04, LAM-05, LAM-06, LAM-07, and LAM-08). Yield and fruit quality traits were evaluated. Partial diallel analysis was carried out to estimate general combining ability and specific combining ability. Additive and non-additive effects were observed for the yield, mean fruit weight, and pulp thickness traits. The lines AF-02, LAM-02, and LAM-03 are the most promising as parents as they more frequently have favorable alleles. The most prominent hybrids in diallel analysis were AF-02 x LAM-02, AF-02 x LAM-03, AF-02 x LAM-04, and AF-03 x LAM-06.

RESUMO: O melão amarelo (Cucumis melo L.) é uma hortaliça de grande importância econômica. Atualmente as cultivares plantadas, em quase sua totalidade, são híbridos. A heterose tem sido explorada no meloeiro, sendo o emprego de híbridos uniformes uma das razões do sucesso da cultura. O objetivo do presente trabalho foi avaliar o potencial agronômico de linhagens e híbridos de melão amarelo. Foi conduzido um ensaio em blocos casualizados com três repetições para avaliar 24 híbridos gerados pelos cruzamentos entre três linhagens elites utilizadas como genitores femininos (AF-01, AF-02 e AF-03), e oito linhagens utilizadas como genitores masculinos (LAM-01; LAM-02; LAM-03; LAM-04; LAM-05; LAM-06; LAM-07 e LAM-08). Foram avaliados caracteres a produção e a qualidade do fruto. Realizou-se a análise dialélica parcial para estimação das capacidades geral e específica de combinação. Observou-se efeitos aditivos e não aditivos para os caracteres produtividade, peso médio do fruto e espessura da polpa. As linhagens AF-02, LAM-02 e LAM03 são as mais promissoras por possuir maior frequência de alelos favoráveis. Os híbridos de maior destaque foram AF-02 x LAM-02, AF-02 x LAM-03, AF-02 x LAM-04 e AF-03 x LAM-06.