Quantitative variation in the tropical maize population, ESALQ-PB1
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Data
2008-04-01
Autores
Andrade, João Antonio da Costa [UNESP]
Miranda Filho, José Branco de
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Editor
Universidade de São Paulo (USP), Escola Superior de Agricultura Luiz de Queiroz (ESALQ)
Resumo
A boa produtividade e os valores intermediários para altura da planta e altura da espiga caracterizam a população de milho ESALQ-PB1 como agronomicamente promissora. São relatadas estimativas de parâmetros para 13 caracteres: altura da planta (PH), altura da espiga (EH), posição relativa da espiga (EP), comprimento do pendão (TL), peso do pendão (TW), número de ramificações do pendão (TB), peso de espigas (EW), peso de grãos (GW), comprimento da espiga (EL), diâmetro da espiga (ED), número de fileiras de grãos (RN), número de grãos por fileira (KR) e prolificidade (PR). Os resultados se referem a um único ambiente (um local e um ano). Foi detectada variação genética para todos os caracteres, e são apresentadas estimativas da variância genética aditiva. Os coeficientes de herdabilidade (indivíduos) variaram de 0,14 a 0,72 e foram considerados altos para PH, EH e TB; intermediários para EP, TL, TW, EL e ED, e baixos para EW, GW, KR e PR. O coeficiente de herdabilidade para médias de progênies mostrou aproximadamente a mesma tendência, variando de 0,40 a 0,75. O maior ganho esperado por seleção foi para TB (27% por ciclo) sob seleção massal e para TW (16,4%) por seleção entre progênies; o menor ganho esperado foi para ED, tanto por seleção massal (1,9%) como por seleção entre progênies (2,9%). Coeficientes de correlação aditiva (rA) 0.5<rA<0.6 foram observados para PH ou EH e para os caracteres de produção (EW e GW) e seus componentes EL e KR, e 0,10<rA<0,44 para PH ou EH e caracteres do pendão. Para os caracteres do pendão a maior correlação foi rA = 0,63 (TB.TW). EP foi correlacionada positivamente com TB, TW, PH, EH e PR; e negativamente correlacionada com ED e RN. As respostas correlacionadas esperadas em diversos caracteres após seleção para GW, EH e TB são apresentadas.
Good yield and intermediate plant height, ear height, and tassel size characterize the maize population ESALQ-PB1 as an outstanding breeding population. Estimates of genetic parameters are reported for 13 traits: plant height (PH), ear height (EH), ear placement (EP), tassel length (TL), tassel weight (TW), tassel branch number (TB), ear weight (EW), total grain weight (GW), ear length (EL), ear diameter (ED), kernel row number (RN), kernel number per row (KR) and prolificacy (PR). Results refer to one location and one year. Genetic variation was detected for all traits, and the estimates of the additive genetic variance are presented. The coefficients of heritability (individual basis) varied from 0.14 to 0.72 and were considered high for PH, EH and TB; intermediate for EP, TL, TW, EL, EP, ED and RN, and low for EW, GW, KR and PR. The coefficient of heritability (progeny mean basis) showed approximately the same trend and varied from 0.40 to 0.75. The highest expected gain from selection was for TB (27% per cycle) under mass selection and for TW (16.4%) under progeny selection; the lowest expected gain was for ED either for mass selection (1.9%) or progeny selection (2.9%). Additive correlation coefficients (rA) of 0.5<rA<0.6 were found for PH or EH and yield traits (EW and GW) and its components EL and KR, and 0.10<rA<0.44 for PH or EH and tassel traits. For the tassel traits the highest correlation was rA = 0.63 (TB.TW). EP was positively correlated with TB, TW, PH, EH and PR; and negatively correlated with ED and RN. The expected correlated responses in several traits after selection for GW, EH and TB are given.
Good yield and intermediate plant height, ear height, and tassel size characterize the maize population ESALQ-PB1 as an outstanding breeding population. Estimates of genetic parameters are reported for 13 traits: plant height (PH), ear height (EH), ear placement (EP), tassel length (TL), tassel weight (TW), tassel branch number (TB), ear weight (EW), total grain weight (GW), ear length (EL), ear diameter (ED), kernel row number (RN), kernel number per row (KR) and prolificacy (PR). Results refer to one location and one year. Genetic variation was detected for all traits, and the estimates of the additive genetic variance are presented. The coefficients of heritability (individual basis) varied from 0.14 to 0.72 and were considered high for PH, EH and TB; intermediate for EP, TL, TW, EL, EP, ED and RN, and low for EW, GW, KR and PR. The coefficient of heritability (progeny mean basis) showed approximately the same trend and varied from 0.40 to 0.75. The highest expected gain from selection was for TB (27% per cycle) under mass selection and for TW (16.4%) under progeny selection; the lowest expected gain was for ED either for mass selection (1.9%) or progeny selection (2.9%). Additive correlation coefficients (rA) of 0.5<rA<0.6 were found for PH or EH and yield traits (EW and GW) and its components EL and KR, and 0.10<rA<0.44 for PH or EH and tassel traits. For the tassel traits the highest correlation was rA = 0.63 (TB.TW). EP was positively correlated with TB, TW, PH, EH and PR; and negatively correlated with ED and RN. The expected correlated responses in several traits after selection for GW, EH and TB are given.
Descrição
Palavras-chave
parâmetros genéticos, variabilidade genética, herdabilidade, seleção recorrente, genetic parameters, genetic variability, heritability, recurrent selection
Como citar
Scientia Agricola. São Paulo - Escola Superior de Agricultura Luiz de Queiroz, v. 65, n. 2, p. 174-182, 2008.