以黄金桂、黄奇、黄观音、铁观音、红芽佛手为亲本,进行早生种与早生种及晚生种与早生种、中生种的人工杂交,观察F₁展叶期的遗传变异趋势。结果表明：①F₁展叶期是以两亲展叶期平均值为中心而呈连续变异的,变幅大。F₁展叶期平均值接近两亲平均值。②早生种×早生种F₁展叶期提早和推迟的正负向超亲遗传现象同时出现。晚生种×早生种F₁展叶期介于两亲之间。晚生种×中生种F₁较多的趋向中生种。③父本对F₁展叶期的影响大。父本早,F₁亦早。父本相同,母本不同,则其F₁展叶期与两亲展叶期的差数有关。两亲差数小,F₁变幅大。鉴此提出,通过早生种与早生种杂交,可以选择比早生亲本更早的新类型。同时,根据父本展叶期、两亲展叶期的平均值与差数,可以预测F₁展叶期的平均值和可能出现的变异范围。

This research adopted the Huangjingui, Huangqi, Huangguanyin, Tieguanyin and Hongyafoshou as parent plants to make artificial hybridization between cultivars with various sprouting date and to observe the trend of genetic variation in the F₁ leaf-expansion period. Results showed that:① The F₁ leaf-expansion periods occurred a successive variation with the average value of their parent leaf-expansion periods as the central value, the variation range was large and the average value of the F₁ leaf-expansion period was close to the average value of their parents. ② In the combinations of early-sprouting and early-sprouting cultivars, the super-parental phenomenon in both positive and negative directions of genetic variation of shortening or postponing the F₁ leaf-expansion period were observed. In the combination of late-sprouting and early-sprouting cultivars, the F₁ leaf-expansion periods were located between their parents. In the combination of late-sprouting and middle-sprouting cultivars, the F₁ leaf-expansion period were mostly close to the that of middle-sprouting cultivars. ③ The male paternal showed more influence on the leaf-expansion period in F₁ generation. When the leaf-expansion period of male parent was earlier, the F₁ leaf-expansion period was also early in F₁ generation. If the leaf-expansion period of paternal plant were same, the leaf-expansion period in F1 generation was related to the difference of the leaf-expansion period between their parents. When the difference between their parental plants was small, the large variation of leaf-expansion period occurred in the F₁ generation. For these reasons, it is possible to acquire the hybrid with the earlier leaf-expansion period than their parental plants via through the hybridization between early-sprouting and early-sprouting cultivars. Simultaneously, it is possible to forecast the F₁ average leaf-expansion period in the F₁ generation and possible variation range in the F₁ generation according to the paternal leaf-expansion period, the average value and their difference of leaf-expansion periods between the two parents.