artificial cross

The seed set was low for both natural and artificial cross pollination with only about one forth of ovules developing into seeds.

矮牡丹的结实率低，平均只有近1／4的胚珠发育成种子。

It has been proved by natural infection and artificial inoculation that cross infection appeared between larger and smaller apple trees. Some mainly cultivars of larger apple trees can be infected by this disease.

经自然感病和人工接种证明，大、小苹果上的黑星病菌可以交互侵染，目前一些主栽的大苹果品种均能感染此病。

Artificial Interspecific Cross Among Seven Species of Dendranthema in China

菊属7个种的人工种间杂交试验

Recent advances in genetic breeding of Agaricus bisporus involving artificial selection, cross breeding, protoplast fusion and gene engineering have been summarized, and the future prospects discussed.

综述了人工选择育种、杂交育种、原生质体融合育种和基因工程育种等双孢蘑菇遗传育种研究的现状及进展，并展望了上述研究领域的发展趋势。

Artificial Neural Network and Cross Section Design of Steel Reinforced Concrete Columns

人工神经网络与劲性混凝土柱截面设计