Abstract
By treatment(dropping) of 0.1~0.4% colchicine solution on the sprouts of winter buds of hard wood cutting slips for 4~5 days, two lines of artificial autotetraploids from Yongchonppong and one line from Yeongbyonppong were bred and the important cultivative characteristics of those new lines were as follows. The greentip sprouting stage of the new bred lines in spring season is later than the parental varieties by two days, but growth speed of the new lines after sprouting was faster than that of the parental varieties reaching the same level development with the parental varieties at the fifth leaf sprouting stage to be mid varieties same as the origins. The leaf shape of the new bred lines was wide round and the petioloes were long and thick. The thickness of leaf was thicker than the parental varieties by 17-33% and single leaf weight was heavy. The leaf area weight increased by 21-31% and the content of chlorophyll was also higher by 11-33%. With all the characteristics, the new breds produced good quality of leaves. The length and number of branches were shorter and less, respectively, than the parental varieties, but the internode length was either same or longer than the parents. Looking at the characteristics, the constitution of shoots was slightly inferior to the parental varieties. The cold hardness expressed by the death top rate of Sawonppong 23 and Sawonppong 24 was same level as that of Yongchonppong, but Sawonppong 25 was stronger than Yeongbyonppong in it with a high infection rate of dwarf disease. The productivity was lower than the parental varieties, but young shoot rate to shoot and branch and the ratio of leaf to young shoot were higher than the parental varieties. The fertility of Sawonppong 23 and Sawonppong 24 was comparatively high with 62% of cross success, but that of Sawonppong 25 was low with 23.9% of cross success.
고조삽목후 삽수의 동아가 발아할 때 0.1~0.4% Colchicine 수용액을 4~5일간 적하하여 용천뽕의 동질4배체 2계통, 영변뽕의 동질4배체 1계통을 육성하였으며 주요 재배학적 특성은 다음과 같다. 1. 봄철의 탈포기는 모품종보다 2일간 늦으나 발아후의 발육속도가 빨라서 5개엽기는 모품종과 동일한 중생뽕이었다. 2. 잎모양은 폭광형이고 잎자루는 길고 굵으며 잎두께는 모품종보다 17~33% 두껍고 1엽중은 무겁고 잎면적중은 21~31% 증가하고 엽록소함량은 11~33% 증가하여 우수한 엽질적 요소를 갖추었다. 3. 모품종보다 가지길이는 짧고 가지수도 적으며 마디사이길이는 같거나 약간 길어지며 굵어져서 가지의 구성요소는 다소 불량하였디. 4. 가지끝마름길이 비율로 나타낸 내동성은 4원뽕 23호, 24호는 용천뽕과 비슷하고 4원뽕25호는 영변뽕보다 강하였고 뽕나무 오갈병 발생율은 높았다. 5. 모품종보다 수량성은 낮고 신초엽량비율과 정엽량비율은 약간 높았다. 6. 4원뽕23호와 24호는 염성이 비교적 높아서 62%의 교잡성공율을 나타내었으나 4원뽕25호는 염성이 낮고 교잡성공률은 23.9%이었다.