Zhengzhou Fruit Research Institute, Chinese Academy of Agricultural Sciences, Henan Joint International Research Laboratory of Fruits and Cucurbits Biological Science in South Asia, Zhengzhou, 450009, China.
Cross Pollenated Plants Department, Horticulture Research Institute, Agriculture Research Center, Giza, 12611, Egypt.
Sci Rep. 2023 Mar 27;13(1):4993. doi: 10.1038/s41598-023-32225-z.
Seed production for polyploid watermelons is costly, complex, and labor-intensive. Tetraploid and triploid plants produce fewer seeds/fruit, and triploid embryos have a harder seed coat and are generally weaker than diploid seeds. In this study, we propagated tetraploid and triploid watermelons by grafting cuttings onto gourd rootstock (C. maxima × C. mochata). We used three different scions: the apical meristem (AM), one-node (1N), and two-node (2N) branches of diploid, triploid, and tetraploid watermelon plants. We then evaluated the effects of grafting on plant survival, some biochemical traits, oxidants, antioxidants, and hormone levels at different time points. We found significant differences between the polyploid watermelons when the 1N was used as a scion. Tetraploid watermelons had the highest survival rates and the highest levels of hormones, carbohydrates, and antioxidant activity compared to diploid watermelons, which may explain the high compatibility of tetraploid watermelons and the deterioration of the graft zone in diploid watermelons. Our results show that hormone production and enzyme activity with high carbohydrate content, particularly in the 2-3 days after transplantation, contribute to a high survival rate. Sugar application resulted in increased carbohydrate accumulation in the grafted combination. This study also presents an alternative and cost-effective approach to producing more tetraploid and triploid watermelon plants for breeding and seed production by using branches as sprouts.
培育多倍体西瓜的种子成本高、过程复杂且劳动强度大。四倍体和三倍体植株产生的种子/果实较少，三倍体胚胎的种皮更硬，一般比二倍体种子弱。在这项研究中，我们通过将西瓜接穗嫁接到葫芦砧木（Cucurbita maxima × Cucurbita moschata）上来繁殖四倍体和三倍体西瓜。我们使用了三种不同的接穗：二倍体、三倍体和四倍体西瓜植株的顶端分生组织（AM）、一节（1N）和两节（2N）的嫩枝。然后，我们评估了嫁接对植物成活率、一些生化特性、氧化剂、抗氧化剂和激素水平的影响，在不同时间点进行了评估。我们发现当使用 1N 作为接穗时，多倍体西瓜之间存在显著差异。与二倍体西瓜相比，四倍体西瓜具有最高的成活率和最高水平的激素、碳水化合物和抗氧化活性，这可能解释了四倍体西瓜的高兼容性和二倍体西瓜嫁接区的恶化。我们的结果表明，高碳水化合物含量的激素产生和酶活性，特别是在移植后的 2-3 天内，有助于提高成活率。糖的应用导致嫁接组合中碳水化合物的积累增加。本研究还提出了一种替代的、具有成本效益的方法，通过使用嫩枝作为芽来生产更多的四倍体和三倍体西瓜植株，用于杂交育种和种子生产。
