Parâmetros genéticos e análise de trilha para o florescimento precoce e características agronômicas da alface

Abstract

Resumo -O objetivo deste trabalho foi avaliar os parâmetros genéticos das características agronômicas e de tolerância ao florescimento precoce de onze cultivares de alface, bem como verificar a existência de associação entre as características. O experimento foi realizado em ambiente protegido, em delineamento de blocos ao acaso, com quatro repetições e doze plantas por parcela. Quarenta e cinco dias após o transplantio das mudas, foram mensuradas as seguintes características: massa de matéria fresca total e "comercial" da parte aérea, massa de matéria seca "comercial" da parte aérea, massa de matéria fresca e seca da raiz, diâmetro e circunferência da cabeça, altura de planta, número de folhas por planta e número de dias até a antese. Há variabilidade genética entre as cultivares, em todas as variáveis, exceto quanto à circunferência de planta e matéria fresca da raiz. As cultivares Regina 500, Lívia e Atração foram superiores quanto ao número de dias para o florescimento e também para as demais características avaliadas. A seleção contra o florescimento precoce ocasionou ganho em todas as características; porém, não interferiu na matéria seca da raiz. A matéria fresca da parte aérea e o diâmetro de cabeça são indicadas para a seleção indireta contra o florescimento precoce.Termos para indexação: Lactuca sativa, ambiente protegido, antese, correlação, pendoamento. Genetic parameters and path analysis for early flowering and agronomic traits of lettuceAbstract -The objective of this study was to evaluate the genetic parameters of agronomic traits and of tolerance to early flowering of eleven cultivars of lettuce, as well as to verify the existence of an association between the characteristics. The experiment was carried out in a protected environment, in a randomized complete block design, with four replicates, and twelve plants per plot. Forty-five days after seedling transplanting, the following traits were measured: total shoot fresh mass, marketable shoot fresh mass, marketable dry shoot weight, fresh and dry weight of roots, diameter and circumference of head, plant height, number of leaves per plant, and number of days until anthesis. There was genetic variability between cultivars for all variables, except for circumference of plant and fresh weight of root. The cultivars Regina 500, Lívia and Atração were superior for number of days to flowering and also for the other characteristics. The selection against early flowering caused gain of all the characteristics, but did not affect root dry matter. Fresh matter of shoots and head diameter are indicated for indirect selection against early flowering.Index terms: Lactuca sativa, protected environment, anthesis, correlation, flowering. IntroduçãoA alface (Lactuca sativa) é uma cultura muito sensível às condições meteorológicas, principalmente ao excesso de chuva e altas temperaturas, e mais adaptada a temperaturas amenas (Oliveira et al., 2004;Souza et al., 2008), com variação de rendimento conforme a cultivar e as mudanças de tempo ocorridas durante o ano.A ...

Estimates of genetic parameters of pigments and agronomic traits in green and purple lettuce

“…The genetic variance was superior to the environmental variance observed for all variables analyzed in the present study, with the exception of the anthocyanin content (Table 2). These results are in accordance with Azevedo et al (2014), who evaluated genetic parameters relating the same characteristics to early flowering and obtained estimates of genetic variance above the environmental variances. This result indicates that the genetic factors have a greater influence on the expression of the characteristic than the environmental factors and allows for the selection of individuals with characteristic expressions above the average (Publio Júnior et al, 2018).…”

“…Estimates of narrow-sense heritability found in this study may be considered high for the number of leaves and plant diameter ( 2 n h = 89.56 and 64.06, respectively). These estimates were close to those found by Azevedo et al (2014), who evaluated 11 lettuce cultivars and found estimates of narrow-sense heritability of 59.39 and 96.77% for the number of leaves and plant diameter, respectively.…”

Genetic dissimilarity between biofortified lettuce genotypes for leaf carotenoid levels

“…Positive correlations were found between most of the agronomic characteristics, a circumstance favorable to the improvement of lettuce (Azevedo et al, 2014).…”

“…Thus, it is noticed that the levels of carotenoid (highly correlated with the SPAD index) (Cassetari et al, 2015), are little influenced by the characteristics of leaf number, stem diameter and plant diameter. Azevedo et al (2014) evaluating 11 lettuce cultivars also found a positive genotypic correlation between number of leaves and head diameter (0.66).…”

Fenotipagem por imagem, estimativas de parâmetros genéticos e índices de seleção em alface biofortificada

“…A razão CVg/CVe apresentou valores superiores à unidade para as variáveis NF (1,04), ANT (1,21), PEND (1,63) (AZEVEDO et al, 2014;OLIVEIRA et al, 2019;SILVA et al, 2019) e ANT (OLIVEIRA et al, 2019), corroborando os resultados do presente trabalho.…”