선행연구인 큰느타리버섯의 자실체 특성연구에 기초하여 속성형질과 품질이 우수한 계통을 선발하여 품질이 우수하면서 조기에 수확할 수 있는 품종을 육성하고자 하였다. 수확소요일수가 우수한 KNR2503과 품질이 우수한 KNR2322를 육종모본으로 정하고 이들 계통으로부터 유래한 단포자의 특징을 조사하고 KNR2322는 자식, KNR2322와 KNR2503은 혼합하여 교배를 실시하였다. KNR2322-4×37은 품질과 갓형태에 있어서 육종학적 가치가 우수하였고, 여기에서 유래한 자식계통 KNR2322-4×37-6×12(B)는 수확소요일이 20일 정도로 길었지만, 무게가 68.5g 품질이 6.5로 우수하여 육종모본으로 선발하였다. KNRR2322-30×KNR2503-60(A)은 수확소요일이 13.5일로 육종모본으로서의 가치가 있었다. 육종모본 A와 B 교배결과 A8B8과 A8B10이 수확 소요일, 무게, 품질이 각각 14.0일, 88.8g, 92.7g, 7.0, 7.1로 우수하였다. 고유성 검사의 일환으로 기존품종(큰느타리3호)를 대조구로 핵산지문법과 대치배양을 실시하였는데, 다형성과 대치선이 존재하여 유전적으로 차별성이 있는 것으로 사료되었다. 선발된 두 계통중 A8B8은 “새송이1호”라고 명명하고 국립종자원에 품종보호등록을 하였다.

The main objectives of IRRI’s variety development should meet the needs of customers/farmers from diverse rice sectors in each target region. The dynamic market change asks rapid variety development with highly valued QTLs/genes. Molecular breeding implemented through the efficient crossing, high throughput genotyping and rapid generation advancement will provide packages to breeders to develop new varieties quickly and more economically. The more efficient and cost-effective marker-assisted backcrossing service will provide the more opportunity for the success in molecular breeding platform. To make MABC system more successful, the development of molecular marker system for the high-throughput SNP genotyping is must. Currently Genotyping Service Lab (GSL) of IRRI provides high-throughput SNP genotyping service using BeadXpress and Fluidigm system. Meanwhile, the linked SNP markers for the specific traits are being developed. For abiotic stress tolerances, the markers for submergence, drought, heat, anaerobic germination, salinity, and phosphorus deficiency for Fluidigm system are being developed and tested in variety diversity panel and segregating populations. In MABC, due to the high number of crossings, the labor- and space-saving crossing system is being developed. As a result of an integrated MABC platform will speed up the development of pre-breeding line which are containing single or multiple QTLs/genes.

The transfer of a biotic resistance gene from indica rice cultivars into japonica cultivars by conventional breeding methods often difficult due to high sterility of the progenies, poor plant type, and linkage drag. Molecular markers provide opportunities to map resistance genes and accelerate the application of marker-assisted backcross(MAB) breeding through the precise transfer of target genomic regions into the recurrent parent. The basis of MAB breeding is to transfer a specific gene/allele of the donor parent into the recurrent parent genome while selecting against donor introgressions across the rest of the genome. The effectiveness of MAB breeding depends on the availability of closely linked DNA markers for the target locus, the size of the population, the number of backcrosses and the position and number of markers for background selection. We have successfully developed Bph18 version of the commercially cultivated japonica elite cultivar by using MAB and incorporating the resistance gene Bph18 that conferred enhanced resistance to BPH. MAB breeding provides a new opportunity for the selective transfer of biotic resistance genes into elite indica rice cultivars devoid of linkage drag. In additon, molecular markers precisely estimate the introgression of chromosome segments from donor parents and can speed up the recipient genome recovery via background selection.