Harminder Singh

Mulching and herbicides in peach: Weed biomass, fruit yield, size, and quality

An experiment was conducted to study the effect of mulches and herbicides on weed population, fruit yield, and quality in peach cv. ‘Earli Grande.’ Covering soil with black polythene mulch (100 μm) resulted in 100% control of weeds at six weeks after treatment (WAT) during both the years of study. However, guinea grass, which had emerged out of the black polythene mulch, reduced the weed control efficiencies (WCE) to 96.3 and 98.5% in 2009 and 2010, respectively, at 12 WAT. Application of straw mulch (8 cm, 15.5 t ha− 1) resulted in higher weed control efficiencies at 6 WAT during 2009 and 2010 (98.4 and 98.2%, respectively). At 12 WAT, this decreased to 90.7 and 93.1% in 2009 and 2010, respectively, due to the emergence of bermuda grass and guinea grass from the mulch. The weed control efficiencies with treatments having diuron as pre-emergence herbicide did not differ significantly from black polythene at 6 WAT. Atrazine and pendimethalin were the next most efficient and did not differ significantly from each other. At 12 WAT, diuron followed by fb glyphosate resulted in higher WCE, and it did not differ significantly from atrazine fb glyphosate. In both years, highest fruit yield (69.3 and 67.9 kg tree− 1, respectively) was recorded with straw mulch (8 cm). Straw mulch (8 cm) also resulted in a 20 and 19% increase in fruit weight (81.9 and 81.4 g during 2009 and 2010, respectively) over manual weeding. Straw mulch (8 cm) did not differ significantly from straw mulch (6 cm), black polythene mulch, and diuron treatments for fruit yield during both years. Conclusively, plastic and straw mulches can be used as an effective chemical-free alternative to manual or chemical weed control in peach.

Effect of Various Training Systems and Spacings on Flowering and Fruiting in Peach cv. Shan-i-Punjab

Peaches grow in a fairly limited range in dry, continental or temperate climates, since the trees have a chilling requirement that tropical or sub-tropical areas generally cannot satisfy except in some parts of Uttarakhand, parts of Uttar Pradesh, Tamil Nadu, North Eastern states, Punjab and Haryana (Pathak and Pathak, 2001). Most cultivars require 500 hours of chilling (0 to 10°C) and during that period plant remains in dormant but still chemical reactions are taking place. It is known that peach is highly vigorous fruit crop and in peach no size controlling rootstock is optimal for all climatic conditions, cultivars and economic situation (Yoshikawa et al., 1989). Out of that reason different systems were studied worldwide in accordance with the specific characteristics of the fruit-growing countries and regions (Van Den Ende et al., 1987).

Effect of training system and in row spacing on yield and fruit quality of peach in the sub-tropical regions

Information on the use of different training systems in peach under the sub-tropics is inadequate. Trees of Shan-i-Punjab peach were planted at two spacings, viz., 5 m x 2 m and 5 m x 3 m and were trained to four training systems, viz., Y shaped, Hedge row, Espalier and V trellis. The fruits harvested from Espalier and V trellis trained trees were superior in fruit quality in terms of fruit size, weight, colour and TSS as compared to fruit harvested from other training systems. Fruit yield was found to be maximum from V trellis trained trees. Trees planted at 5 m x 3 m gave higher fruit yield and better quality fruits as compared to 5 m x 2 m planted trees irrespective of training systems.

Summer stratification and germination: A viable option for recovery of hybrid seedlings in low chill peach and nectarines

In-vitro embryo rescue; and summer stratification and germination under controlled conditions was tested for recovering hybrid seedlings in crosses involving low chilling peach and nectarines. The embryos from all the cross combinations showed very high in vitro embryo germination (>85%) on basal MS medium, which can be effectively performed at hard mature or full ripe stage. The stratification period of the hybrid seed varied from 36.3 days in Shan-i-Punjab × Florda Prince to 44.7 days in Tropic Beauty × Florda Grand. At the end of four weeks of transfering the cultures to culture room, maximum plant height (33.7 mm) was recorded in Shan-i-Punjab × Tropic Beauty, which did not differ significantly from the cross Florda Crest × Tropic Beauty. The fruit development period of the seed parent varied from 78.3 days in Shan-i-Punjab × Tropic Beauty and Shan-i-Punjab × Florda Prince to 104.7 days in Tropic Beauty × Florda Grand. Stratification media of cocopeat + vermiculite + perlite (2:1:1) resulted in the highest seed germination but, the actual germination percentage varied with cross combinations. Highest germination (81.5%) was recorded in the cross FlordaGlo × Tropic Sweet, which did not differ significantly from Tropic Beauty × Florda Grand. It was followed by seed germination (68.0%) in Florda Grand × Tropic Beauty. Under high density nursery system, the hybrid seedlings of FlordaGlo × Tropic Sweet showed highest growth (160 cm) and branches (13). The germination of hybrid seeds was positively correlated (0.86) with fruit development period of the seed parent (FDP) and negatively correlated (−0.85) with chilling requirement of seed parent. The proportion of rosseted seedlings was negatively correlated with FDP (−0.61) and positively correlated (0.39) with chilling requirement of the seed parent. The cross combinations with higher FDP of seed parent resulted in higher seed germination of hybrid seed. Hence, controlled climate stratification and germination after harvest can be a viable option for recovery of hybrid seedlings and reducing the breeding cycle in crosses involving seed parents with higher FDP.

Response of baramasi lemon to various post-harvest treatments

Baramasi lemon is an attractive fruit for its unique flavor and acidity. Harvesting period of winter crop of Baramasi lemon coincides with the cooler part of the year and there is low consumption of lemon fruits during winters, which leads to the glut in the market. Baramasi lemons are sensitive to chilling injury and it is difficult to store in the commercial cold stores. So, there is a need to enhance the shelf-life of Baramasi lemon fruits at ambient conditions. Keeping this in view, an experiment was conducted during 2014 to study the effect of chemicals and modified atmosphere packaging on the storage life and quality of Baramasi lemon fruits. Mature green Baramasi lemon fruits of uniform size and colour were harvested and treated with gibberellic acid (25, 50 &75 ppm), boric acid (1, 2 and 3%) and sodium benzoate (2, 3 and 4%) and packed in low density polyethylene (LDPE) bags. Fruit were analyzed for various physico-chemical characteristics after 15, 30, 45 and 60 days of storage. Results revealed that minimum spoilage and total soluble solids (TSS) and maximum physiological weight loss reduction, palatability rating, acidity were recorded in gibberellic acid @ 75 ppm + LDPE packaging during the entire storage period. It can be concluded that gibberellic acid @ 75 ppm along with LDPE packaging was found to be most effective in extending the post-harvest life of Baramasi lemon fruits at ambient conditions for 60 days.