Rani, RubyAman, Ankita2023-04-152023-04-152022https://krishikosh.egranth.ac.in/handle/1/5810196454Litchi (Litchi Chinensis Sonn.) of the sapindaceae family is one of the important sub-tropical fruit crops of India and require very specific climate for its successful condition. The growth, flowering and yield in litchi is greatly influenced by temperature. Phenology is the study of periodical plant development events and how they are affected by environmental conditions factors mainly temperature. In fact, changes in the time of phenophases of fruit trees are of great economical importance because they have direct impact on factors influencing final fruit yield. Phenological studies in litchi are also important for planned management of orchards and alerting litchi growers against environmental vagaries. BBCH-scale (BBCH = Biologische Bundesantalt, Bundessortenamt und Chemische Industrie) proposed by various workers has its own advantages of its simplicity and ease of use for annual, biennial and perennial plants and it also describes both the vegetative and reproductive stages of plant growth in sequential manner. Thus, an experiment was conducted to study the phenological development in litchi variety Deshi and Kasba using extended BBCH scale at experimental plot of Bihar agricultural University, Sabour that lies in indo gangetic plain of Bihar, India for three consecutive years from 2019 to 2021. The time, duration and prevailing temperature at each phenological stages of litchi were recorded as per extended BBCH scale in which 7 out of 10 principal stages were used, starting with bud development (stage 0) and ending with maturity of fruit (stage 8). Pictures of all phenophases were taken to see the morphological difference among them. Phenological development of all the stages of Deshi and Kasba was found significantly different in each year regarding their time of initiation and duration. The initiation of 1st vegetative flush started after 30-35 days in Deshi and 45-50 days in Kasba after harvest. The bud development (Stage 010) started in last week of June to first week of July in Deshi variety for 1st flush and first week of September for second flush. It was last week of July to first week of August in Kasba variety for first flush in both the year and first week of October for second flush. In variety Deshi phenological development was earlier in 2019 as Compared to 2020 and 2021 and it was delayed in 2020. Similar trend was noted in variety Kasba also. All stages of inflorescence were earlier in Deshi as compared to Kasba in each year of observation. It was also reflected that during 2020 all the mesostages was delayed in both the varieties. It was observed that prevailing temperature greatly influenced time and duration of particular phenophases in both the varieties. Positive correlation between maximum and minimum temperature with stages in both the variety was observed. Varietal difference was also observed in this regard and for stage 500, Deshi took higher temperature as compared to Kasba. However, all other stages, it was lower in Deshi as compared to Kasba. The principal stage flowering started earlier in Deshi than Kasba in all the years. But the phase duration of this stage did not vary much among the variety as it ranged from 30 to 32 days in Deshi and 28 to 33 days in Kasba during the year under study. Changes in leaf nutritional status in different phenological stages was also observed and highest Nitrogen (1.62 %) and Phosphorus content (0.27 %) was noted before beginning of stage 5 i.e. inflorescence stage and Potassium was maximum (1.25 %) at flowering stage. Similarly maximum carbohydrates (7.56 %) at stage initiation of stage 5 i.e. inflorescence stage. This study adds knowledge about year to year phenological development in relation to temperature. However, a long-term monitoring of litchi varieties for their phenophases and their relation to temperature is required to confirm the critical temperature for different phenophases and to see the phenological development in litchi with change in climate.EnglishThesis