Abstract
The aims of the work were to examme the variability induced by EMS (ethyl methanesulfonate) mutagenesis of soybean plants, and to isolate mutants altered in nodulation and other growth characters. Seeds of two soybean cultivars, ‘Hwanggeumkong’ and ‘Baegunkong’ were treated with 30 and 50mM EMS(pH 7.0) for 6 hours and were planted directly in the field. Field emergency of$M_1 seed was averaged to be 61.0%, and frequency of plants with chlorophyll-deficient sectors of the first trifoliolate is about 0.7%. Regardless of varieties and does of EMS, $M_1 plant injury at harvest was present in plant height, pod and seed number per plant when compared to those of original-type soybean plants. The $M_2 variability of nodulation process induced by EMS treatment was found to be narrower than that of shoot dry weight. On the basis of the occurrence of chlorophyll-deficient plants, mutated cell frequency within $M_1 seed ranged from 5.3% to 84.2%, suggesting that mutation frequency on the $M_1 seed induced by EMS occurred partly and randomly regardless of varieties and doses of EMS. The putative mutant, which had more nodulation than original-type plant, was short in plant height. Sparse-nodulating soybean mutant was lower in leaf chlorophyll content and showed reduced growth.
황금콩과 백운콩에 30mM 및 50mM EMS를 각각 종자 1립 당 1ml 수준으로 실온에서 6시 간 처리하여 얻은 $M_1종자를 파종한 다음, 포장출현율 및 $M_1개체들의 형태적 특성의 분포 양상을 검토하고,$M_2세대에서 근류착생 및 기타 돌연변이 출현 양상을 조사한 결과를 요약하면 다음과 같다. 1.$M_1 종자의 포장출현율은 백운콩이 황금콩보다 비교적 높았으나 EMS 농도 처리간 차이는 없었으며, 엽록소 결핍 개체 발생율은 평균 0.7%였다. 2. 수확시 $M_1개체들의 경장, 개체당 협수 및 립수는 무처리개체에 비하여 감소되는 경향이었으며, EMS 처리 농도간 분포차이는 크지 않았다. 3. $M_2 세대에서 엽록소 결핍 개체 출현율에 의하여 판별된 돌연변이 유기율은 평균 2.2%이었으며, 돌연변이가 유기된 $M_1종자는 chimera 현상을 나타내었으며 돌연변이 세포의 비율은 5.3～84.2%로 나타났다. 4. EMS 처리에 의하여 근류착생이 많은 MA48계통과 근류착생이 거의 안되는 MD69계통을 선발하였는데 MA48계통은 엽연소함량이 많았고 MD69 계통은 엽록소 결핍 현상을 나타내었다.
