摘要
Anthracnose, caused by </span><i><span style="font-family:Verdana;">Colletotrichum lindemuthianum</span></i><span style="font-family:Verdana;">, is a major disease of common bean and results in high yield loss. Due to the high degree of pathogenic variability of the fungus and the continual emergence of new races, genetic resistance in the host is not durable. Gene pyramiding using Marker Assisted Selection (MAS) is proposed as a viable approach to improve the durability of major genes conditioning resistance to anthracnose. In this study a common bean line Urugezi x AND 1062 susceptible to anthracnose but already improved for </span><i><span style="font-family:Verdana;">Pythium </span></i><span style="font-family:Verdana;">root rot resistance was improved for anthracnose resistance through a backcross breeding program. Genotypic selection was done in Rubilizi laboratory in Kigali, Rwanada whereas phenotypic selection was conducted in an anthracnose hotspot at Rwerere, a research Centre of the Rwanda Agricultural and Animal Resources Development Board (RAB).</span></span><span style="font-family:""><span style="font-family:Verdana;"> Analysis of variance for effect of bean varieties and anthracnose isolates on disease expression showed significant differences (p < 0.001) among varieties and isolates and for the interaction between isolates and varieties. Developed BC</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;">F</span><sub><span style="font-family:Verdana;">1</span></sub><span style="font-family:Verdana;"> plants were 41% of them resistant and 59% susceptible to anthracnose. However, the observed proportion of 26 resistants and 37 susceptible in BC</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;">F</span><sub><span style="font-family:Verdana;">1</span></sub><span style="font-family:Verdana;"> plants didn’t fit the goodness of fit of the expected proportion of 75 resistants to 25 susceptible. Only 41% of BC</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;">F</span><sub><span style="font-family:Verdana;">1</span></sub><span style="font-family:Verdana;"> plants inherited the resistance genes and were phenotypically resistant. Presence of SCAR-markers, SAB3 and SBB14, in the developed resistant lines </span></span><span style="font-family:Verdana;">h</span><span style="font-family:Verdana;"> suggested successful resistance transfer of anthracnose resistance genes.
Anthracnose, caused by </span><i><span style="font-family:Verdana;">Colletotrichum lindemuthianum</span></i><span style="font-family:Verdana;">, is a major disease of common bean and results in high yield loss. Due to the high degree of pathogenic variability of the fungus and the continual emergence of new races, genetic resistance in the host is not durable. Gene pyramiding using Marker Assisted Selection (MAS) is proposed as a viable approach to improve the durability of major genes conditioning resistance to anthracnose. In this study a common bean line Urugezi x AND 1062 susceptible to anthracnose but already improved for </span><i><span style="font-family:Verdana;">Pythium </span></i><span style="font-family:Verdana;">root rot resistance was improved for anthracnose resistance through a backcross breeding program. Genotypic selection was done in Rubilizi laboratory in Kigali, Rwanada whereas phenotypic selection was conducted in an anthracnose hotspot at Rwerere, a research Centre of the Rwanda Agricultural and Animal Resources Development Board (RAB).</span></span><span style="font-family:""><span style="font-family:Verdana;"> Analysis of variance for effect of bean varieties and anthracnose isolates on disease expression showed significant differences (p < 0.001) among varieties and isolates and for the interaction between isolates and varieties. Developed BC</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;">F</span><sub><span style="font-family:Verdana;">1</span></sub><span style="font-family:Verdana;"> plants were 41% of them resistant and 59% susceptible to anthracnose. However, the observed proportion of 26 resistants and 37 susceptible in BC</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;">F</span><sub><span style="font-family:Verdana;">1</span></sub><span style="font-family:Verdana;"> plants didn’t fit the goodness of fit of the expected proportion of 75 resistants to 25 susceptible. Only 41% of BC</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;">F</span><sub><span style="font-family:Verdana;">1</span></sub><span style="font-family:Verdana;"> plants inherited the resistance genes and were phenotypically resistant. Presence of SCAR-markers, SAB3 and SBB14, in the developed resistant lines </span></span><span style="font-family:Verdana;">h</span><span style="font-family:Verdana;"> suggested successful resistance transfer of anthracnose resistance genes.
作者
Annuarite Uwera
John Nzungize Rusagara
Susan Nchimbi Msolla
Augustine Musoni
Teshale Assefa
Annuarite Uwera;John Nzungize Rusagara;Susan Nchimbi Msolla;Augustine Musoni;Teshale Assefa(Sokoine University of Agriculture, Morogoro, Tanzania;Rwanda Agriculture and Animal Resources Development Board, Kigali, Rwanda;International Crops Research Institute for the Semi-Arid Tropics, Bamako, Mali;Alliance Biodiversity International and CIAT, Arusha, Tanzania)
