© 2017 PP House Infuence of Manual and Chemical Thinning on Yield and Quality of Nectarine [Prunus persica (L.) Batsch var. nucipersica] cv. Snow Queen Rajiv Kumar, Rimpika, N. Sharma, Bunty Shylla * , Anju Thakur and D. P. Sharma Dept. of Fruit Science, Dr. Y. S. Parmar University of Hortculture and Forestry, Nauni, Solan, H.P. (173 230), India Stone fruits have been found to be highly suitable to the mid hill zone of Himachal Pradesh. Among these fruits, nectarine is fast emerging as one of the important and potental fruit due its atractve appearance and beter remuneraton as compared to peaches. Among the various cultvars of nectarines being cultvated in this Zone, Snow Queen is the most important cultvar. But under congenial agro climatc conditons, it invariably bears copiously resultng in small to medium sized fruits which consequently fetches low price in the market. Hence the present studies have been carried out with the objectve to study the infuence of manual and chemical thinning on the fruit yield and quality of Snow Queen Nectarine during 2012 and 2013. Experimental trees were subjected to diferent treatments viz. retenton of 3, 4 and 5 fruits manually, foliar applicaton of Ethrel at 200 and 300 ppm, NAA at 20 and 40 ppm, TDZ at 20 and 40 ppm, Ethrel at 200 ppm+NAA at 20 ppm, Ethrel at 200 ppm+TDZ at 20 ppm and control (water spray) two weeks afer petal fall, with three replicatons using RBD. Hand thinning to retain 3 fruits shoot -1 registered the highest thinning percentage, fruit size, weight and volume with the lowest yield. The fruits of the trees treated with Ethrel at 300 ppm recorded the highest content of TSS, total sugar, reducing sugar as well as fruit colouraton while fruit acidity and frmness were the lowest in these fruits. 1. Introducton Nectarines (Prunus persica (L.) Batsch Var. nucipersica) are the group of peaches ofen referred to as “fuzzy-less peaches” or “shaven peaches” due to the lack of fuzz or short hair on the fruit surface. The absence of fuzz (pubescence) on the nectarine fruit surface giving it a smooth skin appearance is fundamentally the only diference between peach and nectarine, though fuzzy peaches and nectarines are ofen commercially regarded as different fruits. In Himachal Pradesh, its commercial cultvaton is catching up in the mid- hill zones comprising districts of Kullu, Solan and Sirmour though it can also be extended to the other sub humid mid-hill areas of Chamba, Mandi, Shimla and Kangra district. Due its atractve appearance and beter remuneraton in comparison to peaches, nectarine is fast emerging as one of the important and potental stone fruit of Himachal Pradesh. Among the various cultvars of nectarines, Snow Queen is the most important cultvar in the state. Its fruits are very atractve having bright red skin colour with white fesh, cling stone and excellent favour. Under congenial agro climatc conditons, this cultvar invariably bears copiously with small to medium sized fruits which consequently fetches low price in the market. Further, Heavy crop load also results in breakage of limbs and exhauston of tree reserves (Dennis, 2002). For proftable nectarine producton, it is very important to have large and uniform sized fruits. Thinning is one of the important agro techniques that can improve fruit size, colour and quality, besides reducing limb breakage and promotng general tree vigour. Thinning lessens the demand on the tree’s resources so that it is able to make good growth and develop fruit buds for the following year thus avoiding the risk of biennial bearing. It allows sunlight and air to penetrate the branches which improves evenness of ripening. Traditonally, thinning of blossoms or fruit-lets is usually carried out manually. However, this practce is tme consuming, labour intensive and expensive. Therefore, the trend has shifed towards chemical thinning using diferent chemicals such as carbaryl, dinitro compounds, plant growth regulators like Ethrel, NAA, thidiazuron etc. Chemical thinning can be done at pre-bloom, bloom and post-bloom stages; thinning at the earlier two stages is based on the crop potental, whereas thinning at later stage is done only afer assessing the actual crop load and is a beter practce under Indian agro-climatc conditons. However, under the Indian agro-climatc conditon, nectarine being a newly Thinning, yield, quality, nectarine, snow queen Keywords: Abstract Article History Artcle ID: AR1802a Received in 5 th March, 2017 Received in revised form 15 th April, 2017 Accepted in fnal form 30 th April, 2017 Bunty Shylla e-mail: shyllabunty@yahoo.com Corresponding Author Doi: HTTPS://DOI.ORG/10.23910/IJBSM/2017.8.5.1802a 601 International Journal of Bio-resource and Stress Management 2017, 8(5):601-604 Full Research