Accomplishments and impact from breeding for increased forage nutritional value
Accomplishments and impact from breeding for increased forage nutritional value
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DOI：
10.2135/cropsci1999.0011183x003900010003x
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发表时间：
1999-01-01
期刊：
影响因子：
2.3
通讯作者：
Vogel, KP
中科院分区：
文献类型：
--
作者：
Casler, MD;Vogel, KP
尽管有相当多的言论，但直到20世纪60年代，分析化学和瘤胃发酵技术的进步使育种者能够采用有意义的实验室技术，在短时间内重复筛选数千个样本，之前并没有认真努力从基因上提高饲料作物的营养价值。遗传增加的消化率，通常是在体外干物质消化率（IVDMD），已被证明在新品种的至少七个饲料作物，包括豆类，冷季型草，暖季型草，一年生植物，多年生植物。IVDMD的增重率范围为8 - 45 g kg（-1）周期（-1），按百分比计算（0.7-2.5% yr（-1）），与许多谷类作物谷物产量的长期增重相似。在无性繁殖的物种中，所有的遗传变异都可以在一个选择周期中被利用，已经报道了高达11.8%的周期（-1）增益。一般来说，IVDMD的收益可在各种环境和管理系统（包括现场测试）中重复。平均跨物种，IVDMD增加1%通常会导致肉牛（Bos taurus）的平均日增重增加3.2%，因为IVDMD增加通常不会降低饲料产量本身，有时会增加饲料产量，这些收益也转化为每公顷牛肉产量的提高。记录与提高饲料营养价值的育种相关的动物性能提高的能力可以大大提高新品种对饲料生产者的价值，这可以导致新品种的快速采用。
Despite considerable rhetoric, there were no serious efforts to improve genetically the nutritional value of forage crops until the 1960s when advances in analytical chemistry and rumen fermentation technology allowed breeders to adapt meaningful laboratory techniques for repeatably screening thousands of samples in a short time period. Genetic increases in some measure of digestibility, typically in vitro dry matter digestibility (IVDMD), have been documented in new cultivars of at least seven forage crops, including legumes, cool-season grasses, warm-season grasses, annuals, and perennials. The rate of gain for IVDMD ranges from 8 to 45 g kg(-1) cycle(-1), which, on a percentage basis (0.7-2.5% yr(-1)), is similar to long-term gains for grain yield of many cereal crops. In asexually propagated species, in which all genetic variance can be utilized in a single cycle of selection, gains as high as 11.8% cycle(-1) have been reported. Generally, gains in IVDMD are repeatable across a wide range of environments and management systems, including on-farm tests. Averaged across species, a 1% increase in IVDMD generally leads to a 3.2% increase in average daily gains of beef cattle (Bos taurus), Because increased IVDMD generally does not decrease forage yield per se, and sometimes occurs with increased forage yield, these gains also translate to improved beef production per hectare. The ability to document increased animal performance associated with breeding for increased Forage nutritional value can greatly enhance the value of a new cultivar to forage producers, which can lead to rapid adoption of new cultivars.