Mapeamento e validação de QTLs de resistência ao nematóide de cisto da soja
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Data
2006-02-20
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Universidade Federal de Viçosa
Resumo
Visando estudar a resistência da soja (Glycine max (L.) Merrill) ao nematóide de cisto - NCS (Heterodera glycines Ichinohe) e auxiliar a implantação da seleção assistida por marcadores moleculares nos programas de melhoramento, o presente trabalho teve como objetivos: (a) estudar a herança da resistência às raças 3, 9 e 14 do NCS em diferentes populações; (b) identificar e mapear microssatélites ligados ao(s) gene(s) de resistência à estas raças, em uma população de linhagens endogâmicas recombinantes (RILs); (c) validar os marcadores microssatélites identificados, em populações F2 originadas de diferentes fontes de resistência daquelas onde os marcadores foram mapeados; e (d) mapear QTLs para diversas características agronômicas de soja. No estudo de herança foram detectados quatro genes epistáticos para a resistência à raça 14 e três genes epistáticos para as raças 3 e 9 na população de RILs do cruzamento entre Hartwig xY23. Na população F2 do cruzamento Msoy 8001 x Conquista, foi identificado um gene recessivo que condiciona resistência moderada e dois genes recessivos conferindo resistência completa à raça 3. Para a raça 14, na população F2 do cruzamento S5995 x Renascença, foram identificados dois genes recessivos para a resistência moderada. No mapeamento de QTLs nas RILs foram identificados quatro QTLs para a resistência a raça 3 nos grupos de ligação (GL) G, A2, J e M, explicando de 12,9% a 34,8% da variação fenotípica, um QTL para a resistência à raça 9 no GL G, explicando 22% da resistência, e apenas associações significativas entre marcadores e a raça 14, principalmente nos GL G e C2. Para a resistência à raça 3, a seleção assistida realizada com os marcadores mais significativos dos GL G e A2 apresentou resultado similar à seleção fenotípica. Na validação de microssatélites para a seleção assistida de plantas com resistência à 3, confirmou-se a associação de marcadores do GL A2 e G, sendo que juntos os marcadores Satt309 no GL G e GMENOD2B no GL A2 apresentaram 100% de eficiência de seleção (ES). Para a resistência a raça 14, avaliada na população S5995 x Renascença, somente marcadores no GL G apresentaram associação significativa. O Satt309, explicou a maior proporção da variância fenotípica e a melhor combinação de marcadores para a seleção de plantas resistentes a esta raça foi do Satt309 com o Satt356, que juntos proporcionaram 100% de ES. Ganhos similares foram obtidos na seleção assistida e na seleção fenotípica. No estudo de mapeamento de QTLs para características agronômicas, foram mapeados cinco QTLs no GL D1a para as características: dias para o florescimento - R1; altura da planta no florescimento APF; altura da primeira vagem APV; número de vagem por planta NVP; e número de semente por planta NSP; quatro QTLs no GL N para as características: APF; R1; número de nós na maturação NNM; e dias para maturação - R8; e dois QTLs no GL F para NNM e NSP, todos no ano de 2001. Para as avaliações de 2002 foram identificados QTLs nos GL A2 (NNM), C2 (APV, NVP), D1a (R1), N (R8), F (NNM), K (R8, APF e APV), H e J (ambos para NSP). Para a característica produção PRO, avaliada em 2001, foram detectados QTLs nos GL E, G, O e K. QTLs consistentes entre anos foram mapeados para R1 (GL D1a), R8 (GL N) e NNM (GL F). Os intervalos entre os marcadores Satt147 - Satt408 (GL D1a) e Sat_033 Satt237 (GL N), foram significativos para várias características, no ano de 2001, sugerindo efeito pleiotrópico destas regiões para as diferentes características. Os resultados deste trabalho serão úteis para a seleção assistida à resistência ao NCS aos programas brasileiros de melhoramento da soja.
To study soybean (Glycine max (L.) Merrill) resistance to the cyst nematode - NCS (Heterodera glycines Ichinohe) and to help the implantation of the marker assisted selection in breeding programs, the present work was carried with the following objectives: (a) to study the inheritance of resistance to the races 3, 9 and 14 of NCS in different populations; (b) to identify and map microsatellites linked to gene(s) for resistance to those races in a population of recombinant inbred lines (RILs); (c) to validate QTLs in F2 populations originated from different resistance sources from which the QTLs were mapped; and (d) to map QTLs for several agronomic characteristics of soybean. In the inheritance study, four epistatic genes for resistance to the race 14 and three epistatic genes for the races 3 and 9 were detected in the RILs population of the crossing Hartwig x Y23. In F2 population from the crossing Msoy8001 x Conquista, a recessive gene conditioning moderate resistance and two recessive genes giving complete resistance to race 3 were identified. For race 14, two recessive genes for the moderate resistance were identified in the F2 population of the crossing S5995 x Renascença. In mapping of QTLs in RILs, for resistance to NCS, the following were identified: four QTLs for race 3 in the linkage groups (GL) G, A2, J and M, explaining from 12.9% to 34.8% of phenotypic variation; one QTL for resistance to race 9 in GL G, explaining 22% of resistance; and only significant associations between markers and race 14, mainly in the GL G and C2. For race 3, the assisted selection accomplished with the most significant markers of the GL G and A2 showed a result similar to that of the phenotypic selection. In validation of microsatellites for marker assisted selection of plants with resistance to race 3, the association of resistance with markers of GLs A2 and G was confirmed, and together the markers Satt309 in GL G and GMENOD2B in GL A2 showed 100% efficiency in selection (ES). For resistance to race 14, evaluated in the population S5995 x Renascença, only markers in GL G showed significant association with resistance. The Satt309 marker explained the highest proportion of phenotypic variance. The best marker combination for the selection of plants resistant to this race was Satt309 with Satt356, that together provided 100% of ES. In 2001, studying the QTLs mapping for agronomic characteristics, were mapped: five QTLs in GL D1a for the characteristics concerning to days for flowering - R1, plant height in flowering APF, first pod height APV, pod number per plant NVP, and seed number per plant NSP; four QTLs in GL N for the characteristics concerning to APF, R1, node numbers in maturation NNM, and days for maturation - R8; and two QTLs in GL F for node number at maturation NNM, and seed number per plant NSP. In evaluations performed in 2002, the QTLs were identified in GL A2 (NNM), C2 (APV, NVP), D1a (R1), N (R8), F (NNM), K (R8, APF and APV), H and J (both for NSP). For the yield, evaluated in 2001, QTLs were detected in the GLs E, G, O and K. In both years, consistent QTLs were mapped for R1 (GL D1a), R8 (GL N) and NNM (GL F). In 2001, the intervals between the markers Satt147 - Satt408 (GL D1a) and Sat_033 - Satt237 (GL N) were significant for several characteristics, therefore suggesting a pleiotropic effect of these regions for different characteristics. It is worth to emphasize that these results will be useful to the assisted selection for resistance to NCS in the Brazilian soybean breeding programs.
To study soybean (Glycine max (L.) Merrill) resistance to the cyst nematode - NCS (Heterodera glycines Ichinohe) and to help the implantation of the marker assisted selection in breeding programs, the present work was carried with the following objectives: (a) to study the inheritance of resistance to the races 3, 9 and 14 of NCS in different populations; (b) to identify and map microsatellites linked to gene(s) for resistance to those races in a population of recombinant inbred lines (RILs); (c) to validate QTLs in F2 populations originated from different resistance sources from which the QTLs were mapped; and (d) to map QTLs for several agronomic characteristics of soybean. In the inheritance study, four epistatic genes for resistance to the race 14 and three epistatic genes for the races 3 and 9 were detected in the RILs population of the crossing Hartwig x Y23. In F2 population from the crossing Msoy8001 x Conquista, a recessive gene conditioning moderate resistance and two recessive genes giving complete resistance to race 3 were identified. For race 14, two recessive genes for the moderate resistance were identified in the F2 population of the crossing S5995 x Renascença. In mapping of QTLs in RILs, for resistance to NCS, the following were identified: four QTLs for race 3 in the linkage groups (GL) G, A2, J and M, explaining from 12.9% to 34.8% of phenotypic variation; one QTL for resistance to race 9 in GL G, explaining 22% of resistance; and only significant associations between markers and race 14, mainly in the GL G and C2. For race 3, the assisted selection accomplished with the most significant markers of the GL G and A2 showed a result similar to that of the phenotypic selection. In validation of microsatellites for marker assisted selection of plants with resistance to race 3, the association of resistance with markers of GLs A2 and G was confirmed, and together the markers Satt309 in GL G and GMENOD2B in GL A2 showed 100% efficiency in selection (ES). For resistance to race 14, evaluated in the population S5995 x Renascença, only markers in GL G showed significant association with resistance. The Satt309 marker explained the highest proportion of phenotypic variance. The best marker combination for the selection of plants resistant to this race was Satt309 with Satt356, that together provided 100% of ES. In 2001, studying the QTLs mapping for agronomic characteristics, were mapped: five QTLs in GL D1a for the characteristics concerning to days for flowering - R1, plant height in flowering APF, first pod height APV, pod number per plant NVP, and seed number per plant NSP; four QTLs in GL N for the characteristics concerning to APF, R1, node numbers in maturation NNM, and days for maturation - R8; and two QTLs in GL F for node number at maturation NNM, and seed number per plant NSP. In evaluations performed in 2002, the QTLs were identified in GL A2 (NNM), C2 (APV, NVP), D1a (R1), N (R8), F (NNM), K (R8, APF and APV), H and J (both for NSP). For the yield, evaluated in 2001, QTLs were detected in the GLs E, G, O and K. In both years, consistent QTLs were mapped for R1 (GL D1a), R8 (GL N) and NNM (GL F). In 2001, the intervals between the markers Satt147 - Satt408 (GL D1a) and Sat_033 - Satt237 (GL N) were significant for several characteristics, therefore suggesting a pleiotropic effect of these regions for different characteristics. It is worth to emphasize that these results will be useful to the assisted selection for resistance to NCS in the Brazilian soybean breeding programs.
Descrição
Palavras-chave
Nematóide de cisto da soja, Marcadores moleculares, Heterodera glycines, Glycine max, QTLs, Soybean cyst nematode, Molecular markers, Heterodera glycines, Glycine max, QTLs
Citação
FERREIRA, Marcia Flores da Silva. Mapping and validation of QTLs for resistance to soybean cyst nematode. 2006. 124 f. Tese (Doutorado em Genética animal; Genética molecular e de microrganismos; Genética quantitativa; Genética vegetal; Me) - Universidade Federal de Viçosa, Viçosa, 2006.