Performance evaluation of Fremont mandarin on different rootstocks under the hot arid environment of India

Performance of an inter-specific hybrid Fremont mandarin was assessed on different rootstocks in the hot arid regions of India as a potential scion species to expand citrus fruit availability in an arid region. Fremont scion attained superior growth and yield characteristics on Karna khatta rootstock by displaying the greatest plant canopy parameters followed by Rough lemon rootstock. However, the Pectinifera as well as the Troyer citrange resulted in dwarfness of the scion. The scion-rootstock compatibility indicators such as scion rootstock ratio, stionic difference and TCSA which were greatest in the Fremont/Pectinifera combination, confirm that the inhibited tree growth on Pectinifera rootstock was caused by intrinsic features of the rootstock rather than an incompatibility reaction. Furthermore, Karna khatta rootstock resulted in highest fruit yield and related traits followed by Rough lemon and Pectinifera rootstocks. The Pectinifera rootstock resulted in a similar response to all fruit physical attributes i.e., fruit weight, fruit diameter, fruit index and fruiting density, except fruit number. The fruit maturity of Fremont was obtained earliest on Pectinifera, while it was most delayed on Karna khatta and Rough lemon rootstocks. Fruit quality parameters on Pectinifera rootstock were superior to those of common rootstock species (Rough lemon or Karna khatta) including fruit juice content as well as its nutritional constituents like TSS, ascorbic acid, pH, total sugar, organoleptic taste, ripening index, lower content of acidity and rind thickness. The total AAE, total flavonoids, total phenol contents were also noticeably higher than those obtained on other rootstocks, except Troyer citrange. Overall, Fremont mandarin can be considered a promising scion in arid regions to extend the harvesting period of superior quality fruits, especially on dwarfing Pectinifera rootstock. It would further ease harvesting operations vis-a-vis possible attainment of a better micro-climate due to small tree stature and high-density orcharding.