Existence of Vivipary in Mango (Mangifera indica cv. ‘Amrapali’) – A Report

Aim: The Amrapalii cultivar of mango is known for its dwarf stature, high productivity and ability to capture the market late when mango from other regions of the country gets over. Vivipary is of unusual occurrence in mango. The aim of the study is to report the occurrence of vivipary in mango especially in cultivar Amrapali under the sub-Himalayan subtropics of India. Materials and Methods: Incidental occurrence of vivipary in mango has been reported from the Hamirpur district of Himachal Pradesh during the growing season of the year 2021. Upon observance of abnormal protuberances from the fruit surface, the harvesting was commenced at the weekly intervals and the per cent proportion of viviparous fruits was ascertained by cutting the fruits longitudinally and confirming the viviparous germination of the seeds. Weather data of the fruit development state were analysed for the accumulation of heat units and rainfall distribution. Efforts have been made for ascertaining the reason behind the viviparous seed development. Results and Discussion: The proportion of viviparous seeds increased with the progression of time and by the mid of September, more than 12% of seeds were found viviparous. The weather data show that there was an early accumulation of heat units. Also, the rainfall during the period of fruit development was high particularly at the time when fruits were advancing toward maturity. It has been observed that the seed maturity has preceded the fruit pulp maturity and ripening may be due to the early accumulation of heat units and high rainfall. This coincidence might have resulted in precocious germination of seed inside the fruit, leading to vivipary. Conclusion: The development of vivipary in Amrapali mango has been found to be associated with the early accumulation of heat units and high rainfall. Under the current changing climatic scenario, a need has been projected for strategic research for curtailing vivipary incidences and saving economic losses to the growers of late mango varieties in the sub-Himalayan subtropics.

Effects of soil temperature and certain weather parameters on the growth and yield of ragi (Eleusine Coracana)

The influence of soil temperature, air temperature and sunshine hours on the growth and yield of ragi (Eleusine coracana, Geartner) (Var. CO II) was evaluated. The results of analysis indicated that soil temperature at crop growth and flowering stages significantly influenced the yield of grain and straw of ragi, the best fit being at 15 cm depth, Soil temperature at 30 cm depth was higher than the mean air temperature. Accumulated heat units correlated positively with grain and straw of ragi. Sunshine hours also correlated positively with yield of grain and straw.

Heat unit requirement of wheat (Triticum aestivum L.) under different thermal and moisture regimes

An experiment was conducted during 2016-17 and 2017-18 at WTC, ICAR-IARI New Delhi on wheat crop sown on three dates (15th November, 30th November and 15th December) with five irrigation treatments. The results indicated that the number of days required for attaining different phenological stages decreased with delay in sowing.For all the phenological stages, crop sown on 15th November consumed higher heat units and consequently resulted in higher yield and heat use efficiency (HUE) than that of other sowing. However, higher pheno-thermal index (PTI) values were observed for the late sown crop i.e. 15th December. Further, among the irrigation treatments, five irrigations throughout the growing period showed increase in days to physiological maturity as well as heat units and HUE for grain and biological yield as compared to other treatments. Five irrigations throughout the growing period increased the grain yield by 69 per cent and biological yield by 46 per cent that that of one irrigation at CRI stage. However, there was no significant difference observed between four and five irrigations levels. The heat units or GDD had highly significant correlation with biological yield(r=0.91) as well as with the grain yield (r=0.85).

Effect of sowing date, irrigation and mulch on thermal time requirement and heat use efficiency of maize (Zea mays L.)

The field experiments was carried out for three years (2015 to 2017) at the Research Farm, Department of Climate Change and Agricultural Meteorology, Punjab Agricultural University, Ludhiana with maize variety PMH-1 sown on three dates (D1-Third week of May, D2-Second week of June and D3- First week of July) under two irrigation regimes (I1 = IW:CPE 1.0 and I2 IW:CPE 0.75) and mulch application (M1: straw mulch @ 5 tha-1 and M2: without mulch) in a split plot design.Results revealed that the early sown crop(third week of May) took higher number of days and heat units to attain various phenophases. Maize variety PMH-1 consumed maximum heat units of 1952oC days for maturity under early sown condition. The heat use efficiency was highest (3.04 kg ha-1oCday-1)for the crop sown during June. Among irrigation regimes, the HUE was higher (2.89 kg ha-1oC day-1) in IW: CPE = 0.75 level of irrigation ascompared to IW: CPE = 1.00 (2.81 kg ha-1oCday-1) and higher HUE was obtained with mulch application (M1) (2.92 kg ha-1oCday-1) as compared to without mulch (M2) (2.76 kg ha-1oCday-1). The sowing of maize crop during second week of June with irrigation of IW: CPE 0.75 under mulch application have been found to be the most efficient for heat utilisation.

MODELING OF A DOUBLE CIRCULATION RECUPERATOR’S HEAT WORK

Utilization of heat from waste products of heat units’ combustion is one of the most important means of saving fuel and energy resources and improving the environmental performance of the enterprise. Improving the design of heat recuperators and increasing their energy efficiency by improving thermal performance is based primarily on the development of new and improvement of existing methods for calculating heat exchangers. In this paper, based on the method of elementary heat balances, a mathematical model of the thermal operation of a double-circulation recuperator is developed. The use of the described mathematical model of recuperator’s heat work makes it possible to analyze its design in terms of energy efficiency, durability, the ability to reduce heat emissions into the environment.