Effects of Flooding Stress on Growth and Root Physiology and Biochemistry of Grafted Red-seed Watermelon Seedlings

[Objectives]This study was conducted to explore how to improve the waterlogging tolerance of red-seed watermelon through grafting,to provide a theoretical basis for its cultivation in rainy season.[Methods]The effects of flooding stress on the growth and root physiological and biochemical characteristics of grafted and own-rooted red-seed watermelon seedlings were studied using Luffa as rootstocks and"Zhongxin 1"red-seed watermelon as scions.[Results]After flooding stress,the biomass and root activity of grafted seedlings of red-seed watermelon were significantly higher than those of own-rooted seedlings.With the prolongation of flooding stress time,the soluble sugar and proline content showed a trend of first increasing and then decreasing,and the grafted seedlings had a larger increase and a smaller decrease,and were always significantly higher than own-rooted seedlings in the same period.The content of malondialdehyde in the root system of grafted seedlings increased first and then decreased,while it continued to increase in own-rooted seedlings,and the increase in own-rooted seedlings was significantly greater than that in grafted seedlings during the same period.[Conclusions]Grafting on Luffa rootstocks could improve waterlogging tolerance of red-seed watermelon.

Heritability of Main Yield Traits in Red-seed Watermelon and Their Correlation Analysis

[Objectives]This study was conducted to provide a reliable theoretical basis for the correct formulation of breeding programs for red-seed watermelon and the effective breeding of hybrid offspring.[Methods]With local varieties and inbred lines of red-seed watermelon as test materials,the generalized heritability of fruit number per plant,single-fruit weight,single-fruit seed number,single-fruit seed weight,seed kernel weight,1000-seed weight,kernel-producing ratio,seed production ratio and seed volume were estimated by variance analysis;and the heritability,genetic variation coefficients,and correlation of the nine yield traits in 43 red-seed watermelon varieties were studied.[Results]The generalized heritability of fruit number per plant,single-fruit weight,single-fruit seed number,single-fruit seed weight,seed kernel weight,1000-seed weight,kernel-producing ratio,seed production ratio and seed volume were 12.86%,80.14%,75.96%,74.39%,48.01%,17.12%,24.97%,18.60%,and 37.07%,respectively.The heritability of single-fruit weight,single-fruit seed number and single-fruit seed weight was higher,and early-generation individual selection could achieve a better effect on them;and 1000-seed weight and kernel-producing ratio had a higher coefficient of genetic variation,indicating a high selection potential.[Conclusions]Indirect selection could be achieved for traits such as the single-fruit seed number,single-fruit seed weight,seed kernel weight,and seed volume by selecting the single-fruit weight.In the process of red-seed watermelon breeding,traits with high heritability can be selected in early generations of hybrids,thus playing the role of early-generation orientation.

Morphological Diversity Analysis of Red-seed Watermelon (Citrullus lanatus ssp. vulgaris var. megalaspermus Lin et Chao) Germplasm Resources

[Objective] This study aimed to analyze the morphological diversity of red- seed watermelon （Citrullus lanatus ssp. vulgaris var. megalaspermus Lin et Chao） germplasm resources. [Method] Multiple cluster analysis and principal components analysis on the morphological traits of 51 red-seed watermelon germplasm resources were carried out. [Result] The coefficient of variations （CVs） of 39 morphological traits in 51 red-seed watermelon idioplasm resources ranged from 5.37% to 66.95%, with an average of 22.87%. The average of Shannon diversity information indices was 1.55. Among them, the Shannon diversity information index of seed length was the highest （2.16） and that of seed shell figure pattern was the lowest （0.32）. In ad- dition, the morphological diversity information indices of quantity characters were higher than that of quality characters. The principal components analysis revealed that the variance contribution rates of the first, second and third principal compo- nents were 19.49%, 15.32% and 9.55%, respectively. Cluster analysis divided the 51 materials into three broad branches based on the morphological traits. There was only one material in the fist branch and two in the second branch, and all the three materials were wild. The other 48 materials were divided into the third branch and all of them were cultivars. [Conclusion] This study provided a theoretical basis for the protection and utilization of red-seed watermelon resources.

Analyses of energy use and greenhouse gas emissions(GHG)in watermelon production

The aim of this research is to conduct an energy use efficiency and greenhouse gas(GHG)emission analysis in watermelon production that took place in Kırklareli Province of Turkey during the 2021 production season.This research contains calculations of Energy use efficiency,specific energy,energy productivity and net energy,energy input types,GHG emissions and GHG ratio.Survey,observation and data calculations are related to the 2021 production season.The data used in the research were collected from 30 different(accessible)farms through face-to-face surveys with full count method.EI and EO were calculated as 15698.99 MJ/hm^(2)and 104784.91 MJ/hm^(2),respectively.In relation to production inputs,24.29%of the energy inputs consisted of chemical fertilizers energy(3813.34 MJ/hm^(2)),20.04%consisted of transportation energy(3146.19 MJ/hm^(2)),10.63%consisted of diesel fuel energy(1668.52 MJ/hm^(2)),7.44%consisted of human labour energy(1168.09 MJ/hm^(2)),6.50%consisted of plant energy(1021.02 MJ/hm^(2)),5.76%consisted of electricity energy(904.50 MJ/hm^(2)),5.18%consisted of machinery energy(813.44 MJ/hm^(2)),3.36%consisted of irrigation water energy(527.63 MJ/hm^(2)),2.85%consisted of organic fertilizer energy(446.72 MJ/hm^(2)),2.40%consisted of farmyard manure energy(376.62 MJ/hm^(2))and 0.67%consisted of chemicals energy(105.67 MJ/hm^(2)).Energy use efficiency,specific energy,energy productivity and net energy were calculated as 6.67,0.28 MJ/kg,3.51 kg/MJ and 89085.91 MJ/hm^(2),respectively.The utilized total energy input in production was grouped as 27.19%direct energy,72.81%indirect energy,22.55%renewable energy and 77.45%nonrenewable.Total GHG emissions and GHG ratio were determined as 492.82 kg CO_(2)-eq/hm^(2),0.01 kg CO_(2)-eq/kg,respectively.