Augmenting heterosis using Pc FAcr genes for protected conditions and molecular diversity studies in cucumber cucumis sativus L

Abstract

The present investigation was carried out at Vegetable Research Center of G. B. Pant newlineUniversity of Agriculture and Technology, Pantnagar with the objectives to estimate heterosis for newlinemetric and quality traits, GCA and SCA of parents and hybrids, screening for powdery mildew newlinedisease and molecular diversity study in Cucumber (Cucumis sativus L.). The analysis of variance newlinefor RBD and combining ability revealed the significant genetic differences among 44 cucumber newlinegenotypes for the 12 yield contributing traits under study. The magnitudes of PCV estimates were newlinehigher than the corresponding GCV estimates for all the characters. Moderate to high GCV newlinetogether with moderate to high heritability and genetic advance as per cent of mean was reported newlinefor majority of the characters under study except days to first female flower, days to first harvest, newlinedays to last harvest, vine length and internodal length. Three cross combinations namely PPCUC-3 newline× PCUC-8, PPCUC-3 × PCUC-28 and PPCUC-11 × PCUC-8 in 2021 and PPCUC-4 × PCUC-8, newlinePPCUC-7 × PCUC-8 and PPCUC-9 × PCUC-28 in 2022 have significant positive heterosis for newlinemaximum numbers of traits and showed their value in combining ability studies. For quality traits, newlinePPCUC-10 × PCUC-28 followed by PPCUC-3 × PCUC-28 and PPCUC-12 × PCUC-28 have newlinesignificant positive heterosis for maximum numbers of traits. Therefore, these cross combinations newlinecan be commercially exploited for hybrid development after multi location testing. PPCUC-3 was newlineidentified as a best general combiner for maximum number traits followed by PPCUC-9 and newlinePPCUC-10. The best specific combiner were PPCUC-9 × PCUC-51 followed by PPCUC-2 × newlinePCUC-8 in 2021 and PPCUC-10 × PCUC-51 was best specific combiner in 2022 for metric traits. newlineFor quality traits, PPCUC-12 × PCUC-28 followed by PPCUC-4 × PCUC-51 was best combiner. newlineHence, these crosses can be utilized in heterosis breeding for improvement in yield and quality newlinerelated traits. For powdery mildew disease resistant reaction, out of all parents and F1 hybrids only newlinecheck variety Poinsett exhibited moderately susceptible reaction while none of the parents and newlinehybrids showed resistant reaction to powdery mildew. Susceptible reaction against powdery newlinemildew was observed in three genotypes viz., PPCUC-2 × PCUC-28, PPCUC-3 × PCUC-28 and newlinePPCUC-7 × PCUC-8. Eleven SSR primers were used for the molecular diversity analysis. Out of newlineeleven primers, four primers generated polymorphic bands. Total 15 bands were amplified by 11 newlineSSR primers in the 14 cucumber genotypes of which polymorphic and monomorphic bands were 8 newlineand 7, respectively. The range of amplified products was 100-400 bp approximately. Average newlinenumber of bands per primer was 2. The PIC values of SSR markers ranged from 0.133 (SSR newline11742) to 0.408 (SSR 19493) with mean value of 0.262 in which marker, SSR 11742 was least newlineinformative while marker, SSR 19493 was most informative due to highest PIC value among other newlinemarkers, therefore this type of marker system could be efficiently applied to detect polymorphism newlinein cucumber. Jaccard s similarity coefficient varied from 0.71 to 1.00. Minimum Jaccard s newlinesimilarity coefficient was found among PPCUC-11 with PPCUC-2. newline