eng Enviro Research Publishers Current Agriculture Research Journal 2347-4688 2321-9971 2025-04-30 13 1 160 171 24202 article Subhankar Gurung 1 Arun Chettri 2 Aita Rani Subba (Limboo) 1 Arunika Subba 1 Aditya Moktan Tamang 3 Department of Botany, Sikkim Alpine University, Main Campus, Kamrang, Namchi, Sikkim, India Department of Zoology, Sikkim Alpine University, Main Campus, Kamrang, Namchi, Sikkim, India Department of Botany, Sikkim University, 6th Mile, Gangtok, India In the face of sporadic pollinator availability, fruit crops are believed to have evolved selfing, outcrossing, apomixis, or mixed mating strategies to ensure effective reproduction. This study investigates the species’ breeding system and pollination efficiency by evaluating five pollination treatments: open pollination, cross-pollination, geitonogamous self-pollination, autogamy and apomixis. Apis cerana was found to be the most common mandarin pollinator, with a pollination efficiency of 0.5. Sikkim mandarins have partial self-incompatibility, according to field tests, with an index of self-incompatibility index (ISI) of 0.28. Fruit set varied significantly across treatments, with open pollination yielding the highest fruit set (46.00 ± 3.10%), followed by geitonogamous self-pollination (31.00 ± 6.48%), xenogamous pollination (14.00 ± 2.45%), autogamy (4.00 ± 2.29%), and apomixis (5.00 ± 2.45%). ANOVA revealed significant differences in fruit weight (F = 44.299, p < 0.001), diameter (F = 8.679, p < 0.001), and fruit seed count (F = 4.559, p < 0.01), whereas total soluble solids (TSS) and acidity showed no significant variation (p > 0.05). Autogamy generated the lowest average fruit weight (22.56 ± 2.97 g), while open pollination produced the highest (54.65 ± 2.72 g). These results underline the ecological and economic importance of pollination management in citrus plantations in the Eastern Himalayas, emphasizing the need for efficient pollinators for the best fruit set and quality. https://www.agriculturejournal.org/volume13number1/pollination-requirements-and-their-impact-on-yield-of-sikkim-mandarin-citrus-reticulata-blanco-in-an-agricultural-field-in-eastern-himalayas-india/ Apis cerana; Eastern Himalayas; Mandarins; Pollination; Pollinators; Sikkim Mandarin