SHARMA, GIRISHDEEPIKA2017-10-172017-10-172017-10http://krishikosh.egranth.ac.in/handle/1/5810033297ABSTRACT The present investigation entitled “Studies on self-incompatibility and fruit development in strawberry (Fragaria x ananassaDuch.)’’was carried out during 2014 to 2017 in the experimental field of Department of Fruit Science, Dr YS Parmar University of Horticulture and Forestry, Nauni,Solan, Himachal Pradesh. In experiment 1, floral morphology was studied in sixteen strawberry cultivars,Gorella (0.67 cm) had maximum receptacle, ‘Pajaro’ maximum stamen length (0.53 cm),‘Belrubi’ (309.12) and ‘Chandler’ (307.93) highest pistil numbers followed by ‘Gorella’ (301.62). Pistil length was maximum in ‘Gorella’ (2.03 mm). ‘Fern’ recorded maximum pollen viability with acetocarmine ((89.88 %) and erythrcin B (78.20 %) tests. Pollen germination was best with 15 per cent sucrose solution (73.10). In experiment II, different modes of pollination were studied in seven cultivars, fruit set with better fruit size and weight was obtained from cross-pollination, followed by hand and open pollination and least was in self-pollination.Cross pollination increased fruit set (95.75 %), seed germination (94.16 % in ‘Chandler x Gorella’), fruit weight (16.34 g), fruit length (41.15 mm in ‘Gorella’ x ‘Chandler’) and fruit breadth (34.10 mm in ‘Confectura x Gorella’) and reduced fruit malformation (3.40 % in ‘Chandler x Gorella’) compared to other pollination modes.Selfing by bagging reduced fruit set by 33.89 %, seed germination by 25.39 %, fruit weight by 41.00 % and increased fruit malformation by 174 % compared to open pollination. On the basis of fruit set, self-incompatibility index ranged from 0.47 to 0.71 among all the cultivars.In experiment III, Parental lines Gorella and Chandler exhibited good general combining ability for fruit weight, fruit size, number of fruit and flowers per plant, plant height, spread, leaf area and yield/plant. ‘Selva’, ‘Addie’, ‘Ofra’ were goodgeneral combiners for short duration of flowering and early flowering, including ‘Gorella’ for early flowering. Cross combinations, Chandler x Gorella, Chandler x Selva, Chandler x Sweet Charlie, Selva x Sweet Charlie, Selva x Confectura, Gorella x Ofra, Sweet Charlie x Confectura, Selva x Gorella and Selva x Confectura were good specific combiners for fruit weight, size, number of fruit and yield components. ‘Addie x Ofra’ and ‘Selva x Gorella’ were good specific combiners for plant height, while ‘Ofra x Confectura’ was good reciprocal combiner. ‘Confectura x Chandler’ was good reciprocal combiners for early flowering and early fruit maturity, whereas‘Addie x Chandler’, ‘Addie x Selva’, ‘Addie x Gorella’ were good reciprocal combiners for yield components.The estimates of variance ratio were found to be < 1 for almost all the traits included in this study except for plant height and leaf number indicated predominance of non additive gene action.ennullThesis