[Development of new soybean germplasm with null lipoxygenase and Kunitz trypsin inhibitor genes].

Soybean is one of the most important sources of plant protein for human. Soybean protein is a kind of high-quality protein composed of balanced amino acids, which contains all kinds of amino acids, especially 8 amino acids necessary for human. But it also contains some components that are not good for human and affect food quality, such as lipoxygenase (Lox) and trypsin inhibitor (Ti). Those are important anti-nutritious factors. Nutritional value and processing quality of soybean can be improved by means of development of new variety with null Lox and Ti. In this paper, new soybean germplasms that pyramided multiple genes of high quality, null lipoxygenase and trypsin inhibitor genes (Ix1, Ix2, Ix3 and ti) were developed by means of cross and biochemical marker-assisted selection of progenies for null lipoxygenase and trypsin inhibitor genes using known Lox and Ti markers (protein markers). Female parents were soybean varieties Ludou 4, Zhongpin 661, Yudou 8,91D15, wei8640 popularized in Huanghuaihai Plain. Male parents were varieties introduced from US, trypsin-inhibitor (Ti)-deficient varieties P. I. L83-4387 and near isogenic lines of varieties Century for lipoxygenase (Lox)-deficient genes, Century-2 (Ix2), Century-2.3 (Ix2Ix3) and Century-1.3 (Ix1 Ix3). These new germplasms will promote soybean breeding for improved quality production,and utilization.

[Development of a new type soybean germplasm with null lipoxygenase isozymes].

Soybean protein is a kind of high-quality protein composed of balanced amino acids. It contains all kinds of amino acids, especially eight amino acids necessary for human, but also contains some components that are not good for human and affect food quality, such as Lipoxygenase (Lox) and Trypsin inhibitor (Ti). Nutritional value and processing quality of soybean can be improved by means of development of new variety with null Lox and Ti. In this paper, a new type soybean germplasm with null lipoxygenase isozymes was developed by Institute of Crop Sciences, Chinese Academy of Agricultural Sciences through years of biochemical marker assistant selection for null lipoxygenase by means of isoelectric focusing-polyacrylamid gel electrophoresis (IEF-PAGE) in the hybrid progenies of "96P17" (Female parent, a null lipoxygenase 2.3 line) and "93704" (Male parent, a null lipoxygenase 1.3 line). It is the first new soybean germplasm with null Lox1.2.3 genes in our country, which will contribute to soybean breeding for high quality, soybean production and utilization. In this paper, the development process of new type soybean germplasm is described.

[Development of a new soybean variety with null trypsin inhibitor and lipoxygenase 2.3 genes--zhonghuang 16 and its cultivation practices].

Soybean protein is a kind of high-quality protein composed of balanced amino acids, which contains all kinds of amino acid, especially 8 amino acids necessary for human, but also contains some components that are not good for human and affect food quality, such as Trypsin inhibitor and Lipoxygenase. Nutritional value and processing quality of soybean can be improved by means of development of new variety with null Lox and Ti. In this paper, a new soybean variety Zhonghuang 16 (originally name as Zhongzuo 96-952) was developed by Institute of Crop Breeding and Cultivation Chinese Academy of Agricultural Sciences through years of biochemical marker assistant selection for null trypsin inhibitor by Native-polyacrylamid gel electrophoresis (Native-PAGE) and null lipoxygenase by means of isoelectric focusing-polyacrylamid gel electrophoresis (IEF-PAGE) in the hybrid progenies of "ti15176" (Female parent)--a high-yielding, mosaic virus resistant and null trypsin inhibitor line and "Century-2.3" (Male parent)--a null lipoxygenase near isogene line of an elite American variety "Century". This variety was subjected to Beijing regional trial for summer-sowing soybean during 1999-2000, and to Beijing demonstration test in 2001. In 2002, it was passed the examination and approval by the Beijing Committee of Crop Variety Examination and Approval because of its outstanding characteristics such as high and stable yielding, good quality (high protein and fat content, high protein content and good protein quality-null Ti and Lox2.3), disease resistant and good general character. It is the first new soybean variety with null Ti and Lox2.3 genes in our country. In this paper, the development process and cultivation of Zhonghuang 16 were described.