果实产量是番茄最重要的园艺特性。根据前人的报道，SEPMBATA型MADS-box基因SlMBP21具有控制番茄花梗离区形成以及调控萼片大小的功能。然而，我们构建过表达的SlMBP21转基因番茄植株，发现这些转基因植株显示出卷曲的叶子，扭曲和开放的雄蕊，产量降低，并产生了小而轻的种子。我们对功能获得型表型和基因表达水平的研究表明SlMBP21基因在调控叶片形态、花和花序结构、种子大小以及果实产量方面起着重要作用。番茄中SlMBP21的过表达导致叶片卷曲，叶片少，这是由于其对关键的叶片极性相关基因的调控导致上、下轴细胞生长不平衡所致。花和花序结构的缺陷导致果实减少。此外，我们发现了SlMBP21通过抑制参与确定番茄种子发育相关基因的表达并与其他一些MADS-box蛋白(S1AGL11，TAGL1和SlMBP3)相互作用来控制种子大小。因此，这些结果表明SlMBP21的过表达对植物生长和发育，特别是对番茄的果实产量造成多重损害。

The joint analysis of the mixed genetic model of major gene and polygene was conducted to study the inheritance of cryotolerance in cotton during the overwintering period. H077 (G. hirsutum L., weak cryotolerance) and H113 (G. barbadence L., strong cryotolerance) were used as parents. Cryotolerance of six generation populations including P1, P2, F1, B1, B2, and F2, from each of the two reciprocal crosses H077×H113 and H113×H077 were all investigated. The results showed that cryotolerance in cotton during the overwintering period was accorded with two additive major genes and additivedominance polygene genetic model. For cross H077×H113, the heritabilities of major genes in B1, B2, and F2 were 83.62, 76.84, and 90.56%, respectively; and the heritability of polygene could only be detected in B2, which was 7.76%. For cross H113×H077, the heritabilities of major genes in B1, B2, and F2 were 67.42, 68.95, and 83.40%, respectively; and the heritability of polygene was only detected in F2, which was 6.51%. In addition, the whole heritability in F2 was always higher than that in B1 and B2 in each cross. Therefore, for the cryotolerance breeding of perennial cotton, the method of single cross recombination or single backcross should be adopted to transfer major genes, and the selection in F2 would be more efficient than that in other generations.