Observation Of Botanical Characters And Evalution Of Cold Resistance Of Hybrids Derived From The Crosses Of Decaploid Red-Flowered Strawberry

Strawberries belong to the perennial evergreen berry plant of the genus Fragaria of the family Rosaceae and bloom white flowers.Red-flowered strawberry is a new member of the strawberry family and is an intergeneric hybrid（Fragaria×Potentilla）.The red-flowered strawberry has red,and green leaves,and is highly ornamental and practical.However,most red-flowered strawberries have very low cold resistance.In this experiment,the 10x red-flowered strawberry‘No.2’,‘No.6’,‘No.7’and‘No.8’from the hybrids of Pink Princess and J15-10,Pretty Beauty and J15-10 were selected and 12x interspecific hybrids‘J15-10’,red-flowered strawberry variety‘Sijihong’,and cultivar‘Fujieliya’were crossed for the parent material.The seed setting rate and seedling emergence rate of the 8 cross combinations were investigated.Plants,leaves,inflorescences,flowers,fruits,quality,etc.of important character;and the semi-lethal temperature,malondialdehyde content,proline content,soluble sugar content and soluble protein content of the two cross combinations are determined.Based on the analysis of cold resistance,according to the genetic variation of these major traits,some strains with bright colors,excellent fruit quality and strong cold resistance were gradually screened,which laid a certain foundation for red-flowered strawberry breeding.The main results were as follows:Using 10x red-flowered strawberry‘No.2’and‘No.8’for hybridization,a new red-flowered strawberry germplasm was obtained for the large fruit and the fruit character of the red-flowered strawberry was improved.In the forward and reverse crosses,all parents,flowers,and fruit traits of the investigated hybrids.In the hybrid progenies of No.2×No.8there were 85.00%of the corolla diameters showing significantly more than‘No.8’;in the cross-crossing,75.00%of the crosses of the hybrids showed significantly more corolla diameter than the‘No.8’.The flower of the parent‘No.2’is white,and the flower of‘No.8’is light pink.The color of the hybrids of the combination of reciprocal and cross-breeding shows flower color separation.The colors are deep pink,light pink,lightest pink and white,and some hybrids plants.The color of the base of the petal appears dark.Most of the hybrids had smaller fruits,and the variation range of the average fruit weight was 2.15 to 6.03 g in hybrids‘No.2’and‘No.8’,and 70.00%of individuals in the hybrids showed significantly higher levels than those of‘No.2’Fruit weight.The soluble solids contents of‘No.2’and‘No.8’were 9.53%and 8.90%,respectively,and 50.00%of the plants in the reverse cross had a significantly higher soluble solid content than‘No.2’.The contents of Vc in‘No.2’and‘No.8’were 80.71 mg/100 g and 64.25 mg/100 g,respectively.The Vc content in individuals with 30.00%and 20.00%of the positive and negative crosses was significantly higher than that of high-parents‘No.2’.The fruit taste of the hybrids was overall acidic,but 60.00%of the fruits had aroma.On their parents and hybrids of ploidy identification of chromosome,parents‘No.2’and‘No.8’for ten times as much as decaploids（2n=10x=70）,and among the20 hybrids randomLy tested,12 of strains decaploids（2n=10x=70）,2 strains of undecaploid（2n=11x=77）,5 strains of enneaploid（2n=9x=63）,1 strain of octaploid（2n=8x=56）.10x red-flowered strawberry‘No.7’and red-flowered strawberry variety‘Sijihong’the were crossed to improve the flower color of the red-flowered strawberry and obtain a bright new red-flowered strawberry germplasm.The test results showed that the hybirds were significantly separated and the flower color changed from light pink to deep pink,mainly concentrated between pink and deep pink,and there were few pinkish hybrids.There were no white flowers in the progeny that crossed the front and back,and most of them were dark pink.The color of the petal at the base of many flower lines appeared to be dark,and the petal double petals of some strains were obvious.The above results show that the selection of a bright red-flowered strawberry for parental hybridization can improve the color of the red-flowered strawberry and effectively improve the ornamental quality.The ploidy breeding using 10x red-flowered strawberry‘No.7’and 12x interspecific hybrid‘J15-10’resulted in a high ploidy new red-flowered strawberry germplasm and improved the cold resistance of red-flowered strawberry.The test results show that the cross between different ploidy is easy to infertility.We only got the hybrids of‘J15-10’as the female parent,the seed setting rate was 12.61%;in the hybrids of the No.7×J15-10,the leaf length,leaf width,corolla diameter and number of inflorescences per plant showed super-parental plants,among which 33.33%of flowers had a significantly higher diameter than the high-parent‘J15-10’;The semi-lethal temperature,malondialdehyde,proline,soluble sugar and soluble protein content of the hybrids and their parents were measured to analyze the cold resistance.The results showed that the semi-lethal temperatures for‘No.7’and‘J15-10’were-8.24°C and-11.81°C,respectively,indicating that the cold resistance of the parent‘J15-10’was higher than that of the parent‘No.7’.The semi-lethal temperature range of the 10 hybrids ranged from-7.35°C to-12.57°C,with the worst cold-resistant strain being A₄（-7.35°C）and the cold-resistant one being A₇（-12.57°C）.The LT₅₀ of 30.00%of the individuals in the hybrids was significantly higher than that of the high affinity‘J15-10’,with30.00%of the LT₅₀ being significantly lower than the low affinity of the‘No.7’.With the decrease of temperature,the content of malondialdehyde in the leaves of hybrids showed a trend of increasing first and then decreasing.The change trend of proline content was also basically consistent and showed an upward trend.About 70.00%of the hybrids had a significantly higher cold resistance than the red-flowered strawberry parent‘No.7’,improving the cold resistance of the red-flowered strawberry.Hybrids of 10x red-flowered strawberry‘No.6’and the cultivar‘Fujieliya’were used to obtain high-ploidy red-flowered strawberry germplasm.The test results show that the cross between different ploidy is easy to infertility.We only got the hybirds of the‘Fujieliya’as the father,the seed setting rate was 33.7%,and the emergence rate was 19.33%;the descendants of the Fujieliya×No.6 plant height,crown diameter,leaf length,leaf width,and corolla diameter all showed super-parent plants;the hybrids also appeared to be isolated in colors of pink,light pink,lightest pink,and white.