Yadav, S.S.Poonam2020-02-042020-02-042019http://krishikosh.egranth.ac.in/handle/1/5810142444The present study was carried out on six early sown genotypes of rapeseed-mustard at Research Area of Oilseeds Section, Department of Genetics and Plant Breeding, CCS Haryana Agricultural University, Hisar during 2018. A total of 17 insect species visited flowers of early sown genotypes viz., 9 Hymenopterans, 3 Dipterans, 4 Lepidopterans, and 1 Coleopteran. The abundance (bees/m2/5 min) of A. florea was highest (8.5) followed by A. mellifera (3.9), A. dorsata (3.6) and A. cerana (3.1). Abundance of bee species was maximum (5.6 bees/m2/5 min) in genotypes TH 68 and SANGAM. A. cerana foraged maximum number of flowers per minute (18.20) followed by A. dorsata (17.57), A. mellifera (17.32) and A. florea (6.45). Foraging rate (flowers/min) of all bee species was maximum (14.98 and 14.90) in genotypes TH 68 and SANGAM. Time spent per flower (sec) was maximum (5.3) by A. florea followed by A. dorsata (1.7), A. mellifera (1.6) and A. cerana indica (1.3). The maximum time spent per flower by all bee species (2.6) was in genotype PDZ 9. Nectar or pollen gatherers were maximum in A. dorsata (37.8% and 25.6%, respectively), while both nectar and pollen gatherers were maximum in A. cerana (45.3%). Nectar foraging, pollen foraging and both nectar and pollen foraging was maximum at peak flowering (36.0%), peak flowering (23.8%) and flowering cessation (42.9%), respectively. Out of the total foragers, top workers were maximum in A. dorsata (97.8%), while side workers were maximum in A. florea (41.0%). Based on flowering phenology, TH 68 genotype was the earliest (33.7 and 85.3 DAS) while RH 725 was the latest (39.7 and 91.7 DAS) to initiate and cease flowering. The flower morphological parameters of different genotypes i.e. mean flower length and breadth varied from 1.40-1.53 cm and 1.61-1.79 cm respectively, flower color was bright yellow, corolla and calyx length ranged from 0.84-0.88 cm and 0.56-0.61 cm respectively, ovary dimensions (length and breadth) were in the range 3.68-3.76 and 2.14-2.18 mm in different genotypes. Mean amount of Dry Nectar Sugar varied from 0.77-0.82 mg, 0.79- 85 mg and 0.61-0.69 mg per flower at flowering initiation, peak and cessation respectively and the genotypes TH 68 and SANGAM were consistently superior nectar-sugar producers throughout the study. Total Soluble Solids of flower nectar (or total sugar content in %) varied from 14.8 % to 38.2 %. The energy reward in studied genotypes varied from 12.9-13.7, 13.2-14.3 and 10.2-11.5 joules per flower during flowering initiation, peak and cessation respectively.ennullThesis