| Seed-used pumpkin(Cucurbita pepo L.)is also known as Zucchini,it mainly grown in Inner Mongolia and other areas,it has good nutritional.Seed-used pumpkin is cross-pollination crops,fruiting is mainly based on artificial pollination,high pollen activity is key to successful artificial pollination.Many research showed that pollen activity was strongly related to temperature and time,so it was necessary to explore the relationship pollen viability of temperature and time.To rapidly innovate germplasm resources and shorten the breeding years,the breeding of hybrid varieties has become one of the hot spots in modern breeding research,it is the most basic and effective method,the utilization of heterosis can shorten the breeding cycle.Using the pollen of seed-used pumpkin(Cucurbita pepo L.)inbred line Hongchang211 as the test material,the pollen viability was measured from 7:00 to 14:00 by TTC staining method in order to determined the time point of the highest pollen viability.Pollen was collected at pollen activity peak point,then pollen activity was detected at 0°C,4°C,25°C storage 0h,24 h,48h,72 h,96h in order to investigate the effects of different storage temperatures and timing on the viability of seed pumpkin pollen.The pollen stored at 0℃,4℃ and 25℃ for 24 h,48h and 72 h was self-pollinated to explore the relationship between pollen viability and fruit development.The seed-used pumpkin parental inbred lines was selected as experimental materials,male parents were No.7,22,F4,F5,F6,F7,female parents were No.4,10,12,14,19 respectively.According to the design of Griffing incomplete diallel cross,heterosis and combining ability of seed-used pumpkin 12 traits were studied and analyzed in order to screen out the combinations with strong superiority and high combining ability.The study provides a theoretical basis for future seed-used pumpkin hybrid breeding.The main results are as follows:1.The pollen viability of seed-used pumpkin(Cucurbita Pepo L.)reached the highest at 9:00;then decreased gradually over time under the conditions of 0℃,4℃,and 25℃.Besides,the pollen viability decreased faster at 25℃ than 0°C and 4°C,it was more suitable for storing pollen at 0°C and 4°C;The pollen was collected in advance and stored in different temperatures and times before pollination.The transverse diameter of fruit at 25℃ for 24 h was biggest,the seed thickness and weight at 4℃ for 24 h was biggest,the pulp thickness at 0℃ for 48 h was largest,other traits stored at 0℃ for 24 h was largest.2.11 parents were divided into three groups by cluster analysis of agronomic traits and general combining ability.Among them,No.4,F7,10,12 were divided into the first group,No.7,F5,14,F4,19 were the second group alone,No.22 and F6 were belonged to the third group.The overall traits of the second group were higher than those of the third group,the third group hed the lowest quality traits.3.Accoreding to Heterosis,a batch of strong and advantageous combinations were Screened out.The combination of 7×10,22×4,22×10,F4×10 was excellent in single fruit weight and volume.The combinations of 22×4,F7×4,F7×12 showed high Seed yield and Seed thickness.The combinations with the best quality traits were F4×10,F4×12,22×14,F4×19,respectively.4.Through general combinatorial capability analysis,parents possessed the biggest GCA value of fruit volume and weight were No.22,F4,F5,F6;Parents possessed the biggest GCA value of number and weight of seeds was No.22.Parents possessed the biggest GCA value of seed size were No.10,19.In the quality traits,parents possessed the biggest GCA value of soluble sugar,crude fat,crude protein were No.F6,F5,F4.Through special combining ability analysis,the strong dominant combinations in fruit traits were22×4,7×10,F6×19;the strong dominant combinations in seed traits were 7×10,22×19,the strong dominant combinations in soluble sugar,crude fat,crude protein were F5×19,F5×10,F4×12,respectively. |
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