Late leafing FaBaAg1 Persian walnut (Juglans regia L.) promising genotype as the new selection from Tarbiat Modares University fruit trees breeding program

Persian walnut (Juglans regia L.) as its name suggests originated from Persia (Iran). After pistachio, it is the second important nut crop in Iran which is propagated by seed; thus, its walnut populations represent a wide range of phenological and pomological variations. Recently, climate change has increased the risk of late-spring frost in walnut orchards. Hence, identifying late-leafing superior genotypes is an effective approach to escape this phenomenon. To identify superior genotypes of walnut in southwestern Iran, this study was carried out to evaluate the walnut population in Fars province (Bavanat, Eqlid, and Sepidan) during 2010-2015. For this purpose, 81 out of 412 walnut genotypes in Bavanat, 48 genotypes in Eqlid, and 40 genotypes in Sepidan were finally evaluated in aspect of phenological and pomological characteristics. We selected 16, 9, and 10 walnut superior genotypes in Bavanat, Eqlid, and Sepidan, respectively. Nut and kernel weight and nut size of the selected superior genotypes were more than 'Chandler' commercial as a standard cultivar. Between these superior genotypes, the FaBaAg1 genotype was an exception; because its bud break date was 30 days later than the reference standard during the five-year evaluation. Despite the severe chilling in 2013, the production of FaBaAg1 was satisfactory. Interestingly, the FaBaAg1 genotype was a homogamous genotype with high yield and lateral bearing habit. Based on the results, FaBaAg1 had superior genotypes with large nut (14.96 g), high kernel percentage (51.05%), and extra light kernel. In general, the FaBaAg1 genotype is not only a desirable parent for the future walnut breeding program but also has the potential to introduce as a late-leafing commercial walnut cultivar.