Comparison of Three Selection Indexes for Selecting Varieties from Performance Trials of Corn, Zea mays L.

옥수수의 생산력 검정시험에 대한 3가지 선발지수의 효과비교

Three kinds of selection indexes were calculated and compared for effectiveness in selecting best performing hybrids from yield trial of corn. The following four characters were used in calculating indexes; yield, moisture content, and root and stalk lodging. 1. Among three indexes calculated, William's base index was more simple in calculation and more efficient in selection of a hybrid than other indexes. 2. Pesek and Baker's estimated index was considered less effective in this test, because of low estimation of genetic variance and covariances of characters from the limited materials and years of experiment. 3. Index calculated according to the Purdue University method (1976) was least effective, even though calculation was simple and easy. The less effectiveness of the index was due to the fact that equal importance of characters were given to each character without considering the differences in economic weight of each character. 4. Equations for expressing moisture content and root and stalk lodging in terms of market price were formulated and they were as follow : 1) Moisture content : $(Y-15.5){\times}$0.0065{\times}bushels/acre$, where Y was the average moisture content of a hybrid at the time harvest. The $0.0065 was the expenses required for removing one per cent of moisture from a bushel of shelled corn in 1976. 2) Root and stalk lodging:$Percent\;lodging{\times}price/Bu.{\div}50{\div}average$ yield of all entries in the test.

옥수수의 우수 품종선발을 위하여 3가지 선발지수를 계산하여 이들 지수의 효과를 비교하였든바 1. William의 기초지수가 가장 계산하기도 쉬웠고 우수 품종선발에서도 효과적이었다. 2. Pesek과 Baker가 제창한 선발지수법은 관여형질의 유전분산 및 공분산을 계산하는데 까다로웠고 또한 공시품종수가 적든가 시험연수나 장소가 많지 않은 경우에는 이들 유전분산 및 공분산이 낮았으며 본 실험에 있어서는 큰 효과가 없었다. 3. 퍼듀 대학의 지수계산법은 계산도 용이하여 사용하기에 편리하였지만 다만 관여형질 등에 대한 중요도를 모두 동일시 하는데 큰 결점이 있었다. 4. 관여형질들을 경제적 가치로 환산하는데 다음과 같은 공식을 이용하였다. 1) 수분함량 : $(Y-15.5){\times}$0.0065{\times}$분셀/에카 여기서 Y는 수확시 수분함량이었고 $0.0065는 1붓셀의 옥수수에서 1%의 수분을 건조시키는데 요하는 경비였다. 2) 뿌리 및 줄기도복 : 도복율(%)${\times}$붓셀당가격${\div}$50${\div}$전체시험구의 평균수량.