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在马里兰州的两个地点进行了杂交研究,其中包括9个亲本(3个马里兰烟、3个白肋烟和3个烤烟的栽培品种)、36个 F_1杂种和21个 F_2杂种。目的是要测定类型内和类型间杂种群体在几个农艺和化学性状上的遗传变异量,获得杂种优势和配合力的估值,确定白肋烟和烤烟栽培品种在马里兰烟育种课题中的潜在用途。在所测定的多数性状上,9个亲本与36个 F_1杂种之间表现了相当大的变异。从平均数来看,F_1杂种比亲本的产量、价格、填充值都高,但节间长,总氮量低,燃烧性差,开花早。总的看来,类型间杂种比类型内杂种表现出较大的杂种优势。然而,在本研究中,类型间杂种一般并不显著地优于最好的亲本。F_2杂种在产量、价格、株高、节间长度和到开花的天数等方面都有显著的自交衰退现象。在10个性状中,有9个性状的一般配合力的方差值很显著。特殊配合力的方差值只是在节间长度上表现显著。配合力效应与地点之间的交互影响,在4个性状上表现显著;一般配合力和特殊配合力各在2个性状上表现显著。
Hybridization studies were conducted at two locations in Maryland, including nine parents (three Maryland tobacco, three burley tobacco and three flue-cured tobacco cultivars), 36 F_1 hybrids and 21 F_2 hybrids. The aim is to determine the amount of genetic variation in several agronomic and chemical traits in and within a type and to estimate the heterosis and combining ability and to determine the potential of burley and flue-cured tobacco cultivars in Maryland tobacco breeding programs use. In most of the traits tested, there was a considerable variation between the 9 parents and 36 F1 hybrids. From the average, F_1 hybrids had higher yield, price and filling value than the parents, but the length of internode, the amount of total nitrogen was low, the combustibility was poor, and the flowering was early. In general, hybrids of the genotypes showed greater heterosis than the hybrids within the genotype. However, in the present study, inter-type hybrids generally did not significantly outperform the best parents. F_2 hybrids had significant self-fertility decline in yield, price, plant height, internode length and flowering days. Among 10 traits, the variance of general combining ability of 9 traits was significant. The variance of special combining ability is only significant in internodal length. The interaction between the combining ability effect and the locality showed remarkable performance on the four traits. The general combining ability and the special combining ability showed remarkable performance on the two traits.