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Open Access
Influence of rootstocks on growth, yield and fruit quality of Kinnow mandarin
(Punjab Agricultural University, Ludhiana, 2021) Mashaal, Jamaluddin; Uppal, Gurteg Singh
The present study entitled "Influence of rootstocks on growth, yield and fruit quality of Kinnow mandarin" was carried out during 2020-21 in the Department of Fruit Science, Punjab Agricultural University, Ludhiana. Kinnow mandarins budded on six rootstocks viz. Kuharske, Rich 16-6, Swingle, Troyer, Carrizo, and Rough Lemon were used in this study. Carrizo rootstock had the highest mean rootstock: scion diameter ratio (0.94), followed by Rough Lemon (0.92), significantly greater than all other rootstocks. However, the bark thickness of rootstock and scion was significantly higher in Troyer (2.1 mm) and Swingle (2.1 mm) rootstocks, respectively. The largest tree canopy volume of Kinnow trees was recorded on Carrizo rootstock (10.89 m3), significantly higher than all other rootstocks. However, the least was recorded on Swingle rootstock (2.25 m3). The mean fruit weight and fruit yield of Kinnow were significantly higher on Carrizo (186.25 g, 68.27 kg/tree), followed by Rough Lemon (168.58 g, 63.62 kg/tree), which were significantly higher than all other rootstocks. Swingle rootstock had the highest mean yield efficiency (9.77 kg/m3) compared with different rootstocks. A significantly higher photosynthesis rate was recorded on Carrizo (5.41μmol m-2 s-1). Kinnow trees had the highest fruit TSS/acidity (12.94) and juice content (52.5%) budded on Carrizo (12.94), followed by Rough Lemon (11.85, 50.2%) rootstock, which was significantly higher than all other rootstocks. However, Kinnow fruits on Rough Lemon recorded the highest ascorbic acid levels ((31.10 mg/100ml juice), and it was at par with Carrizo (30.25mg/100ml juice). Citrus Colour Index (CCI) values for fruit epicarp, pulp, and juice were the highest on Swingle (24.7), Troyer (11.3), and Carrizo (11.1), respectively, which indicated that these rootstocks had higher colour development. The leaf macro and micronutrient levels were also varied in Kinnow tree budded on different rootstocks. Nitrogen, phosphorous, and potassium contents were higher in Rich 16-6 (2.45 %), Troyer and Rich 16-6 (0.18 %), and Troyer (0.94%), respectively. The magnesium, zinc, calcium, and iron contents were maximum in Kinnow leaves budded on Swingle rootstock. However, Carrizo recorded significantly higher Mn (54.17 ppm) content. The study concluded that Carrizo and Rough Lemon rootstock are promising rootstocks for Kinnow mandarin for higher fruit quality and yield. Furthermore, Swingle rootstock is highly dwarf rootstock for having higher yield efficiency and better fruit colour development.
Open Access
Effect of plant spacing on vegetative and reproductive behaviour of guava (Psidium guajava L.) cv. Shweta
(Punjab Agricultural University, Ludhiana, 2022) Chawla, Himanshu; Arora, N.K.
The present investigation on the effect of plant spacing on vegetative and reproductivebehaviour of guava (Psidium guajava L.) cv. Shweta was carried out in the Fruit Research Farm, Department of Fruit Science, Punjab Agricultural University, Ludhiana during the year 2021- 22. The observations were recorded on five-year-old plants of guava cv. Shweta at densities viz. 6x5 m, 5x5 m, 5x4 m, 5x3 m, 4x4 m and 4x3 m. Each replication consists of a unit of five trees. The experiment was laid out as per Randomized Block Design. The present investigation revealed that characters like scion girth, stock girth, scion stock ratio, canopy volume and stomatal density increase with an increase in plant spacing while plant height, leaf size and crotch angle have reversed correlation with spacing. Fruiting attributes viz. flower bud density (38.86 %), fruit set (66.12 %) and fruit retention (61.22 %) were recorded higher in trees spaced at 6x5 m as compared to other spacings; whereas, trees planted at closers pacing (6m x 3m) has taken higher 76 days from fruit set to maturity. The number of fruits per tree, fruit yield per tree, fruiting density and yield efficiency (maximum in 5x5 m spacing) were increased with an increase in plant spacings (4x3 m to 6x5 m) while seed number per fruit was found to be decreased. Quality characters namely palatability rating (8.9), TSS (12.6 %), pulp content (93.72 %), vitamin C (228.1 %), total sugars (8.42 %) and pectin content (1.01 %) were found maximum in winter season crops specifically, at wider spaced plants (6x5 m and 5x5 m). With wider plant spacing (from 4x3 m to 6x5 m), solar radiation interception and canopy temperature increased with an increase in the spacing of plants while the relative humidity was found to be decreased. The present study suggested that guava planted at 5x3 m (267 trees/ acre) registered higher yield per acre as compared to others treatments. However, tree spaced at 5m x 5m had significantly higher yield vis-à-vis improved fruit quality as compared to trees planted at recommended spacing i.e. 6m x 5m.
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Effect of surface coatings and pomegranate peel extract on postharvest life and quality of pear fruit under low temperature storage
(Punjab Agricultural University, Ludhiana, 2021) Megha M; Gill, PPS
The present investigation entitled “Effect of surface coatings and pomegranate peel extract on postharvest life and quality of pear fruit under low temperature storage” were conducted in Post Harvest Laboratory, Department of Fruit Science PAU, Ludhiana. In experiment-I the fruits were coated with chitosan (CH 1 % & CH 2 %), pomegranate peel extract (PPE 1 % & PPE 2 %) and combined coatings of chitosan with pomegranate peel extract (CH 1 %+ PPE 1 %, CH 1 %+PPE 2 %, CH 2 %+PPE 1 % & CH 2 %+PPE 2 %). In experiment-II the fruits were coated with sodium alginate (SA 1 % & SA 2 %), pomegranate peel extract (PPE 1 % & PPE 2 %) and combined coatings of sodium alginate with pomegranate peel extract (SA 1 %+PPE 1 %, SA 1 %+PPE 2 %, SA 2 %+ PPE 1 % & SA 2 %+PPE 2 %). The fruits dipped in distilled water were used as control treatment. Coated and control fruits from both the experiments were packed in corrugated fibre board (CFB) boxes and stored for 67 days at 0-10C and 90-95 % RH. Afterwards, the stored fruits were analyzed for various physico-chemical quality attributes at different storage intervals i.e at 30, 45, 60 and 67 days after storage. Results revealed that fruits coated with CH 2 %+PPE 2 % and SA 2 %+PPE 2 % were effective in maintaining the fruits quality by reducing the loss in weight, colour changes and activities cell wall degrading enzymes like pectin methylesterase (PME), polygalacturonase (PG) and cellulase, retained higher fruit firmness, TSS, sugars, titratable acidity, vitamin C, total phenolics content and total antioxidant activity. These treatments suppressed spoilage, internal browning by delaying rise in polyphenol oxidase activity (PPO) and restrict the accumulation of malondialdehyde (MDA) content and colour changes of fruits.
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Mapping of Phytophthora resistance in intergeneric rootstock population of citrus
(Punjab Agricultural University, 2023) Amandeep Kaur; Sidhu, Gurupkar Singh
The investigations entitled “Mapping of Phytophthora resistance in intergeneric rootstock population of citrus” were carried out in 2020-22. In the present study, screening of Phytophthora related traits of 88 F1 hybrids population (pseudo-testcross) of Rough lemon × Swingle citrumelo was done by spore suspension and filter method. Data were recorded after 90 days of inoculation for different symptoms and growth attributes related to Phytophthora. Phenotypic characterization for qualitative and quantitative characters of F1 hybrids were done based on IPGRI descriptor. Hybrids were showed great variation in percentage of unifoliate, bifoliate and trifoliate leaves, spine length, habitus, branch size, shoot tip colour, young leaf colour, adaxial colour, abaxial colour, leaf lamina shape, leaf apex, leaf margin and petiole colour. Based on the studied 14 attributes, 88 F1 rootstock hybrids revealed different degree of response to Phytophthora. Out of 14 traits, feeder root rot rating, chlorotic leaves and gummosis rating scale (0 to 4), 23 plants were highly susceptible, 19 plants susceptible, 6 plants moderately resistant, 12 plant resistant and 28 plants in highly resistant. In vitro filter method, lesion size was used to find the degree of resistance and observed that 20 were highly susceptible, 19 susceptible, 12 moderately resistant, 13 resistant and 24 in highly resistant. For genotyping, 165 SSR markers were used for parental polymorphism. Further, a genetic linkage map of citrus F1 hybrids has been constructed by using 116 polymorphic SSR markers comprising of 9 linkage groups, spanning a distance of 1476.19 cM. From the identified, twenty six major Quantitative trait loci (QTL), two QTLs for feeder root rot rating observed on chromosome 2 at 32.54 cM and 14.26 cM having Left flanking marker HvSSRCM-241. A total of 2 QTLs (qGR.RL.pau-5 and qGR.RL.pau-8) for gummosis rating were detected on LG5 & LG8. The proportion of the total variation (R2) ranged from 10.98 to 14.52%, respectively. Third experiment was conducted for mass multiplication and conservation of potential hybrids through cutting. Different types of cutting viz., soft, medium and hard wood cuttings from unifoliate and multifoliate hybrids in rainy and spring season were treated with 500, 1000, 1500, 2000 ppm IBA along with control. Among the cutting taken, medium wood cutting during rainy season and spring season in unifoliate performed better in all the parameters whereas during spring season hardwood cutting of multifoliate hybrids performed better. IBA concentration @ 1000 ppm followed by 500 ppm was the best concentration for all the parameters. Overall, the unifoliate hybrids RL×SW-19 & RL×SW-29 and multifoliate hybrids RL×SW-6 & RL×SW-7 were performed better for all the parameters. The phenotypic linkage so constructed will pave the path for high resolution mapping of Phytophthora resistance traits with high throughput marker segregation techniques like genotyping by sequencing on citrus genetic map. Cutting propagation will provide new insights for future mass multiplication from the limited material.
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Physiological and anatomical alterations in wilting of guava (Psidium guajava L.) trees and its amelioration using ethylene inhibitor
(Punjab Agricultural University, 2023) Naik, Eslavath Khamdar; Brar, J.S.
The guava wilt disease is the foremost threat for guava cultivation not only in India, but also in all major guava growing countries. Hence; the present investigation was planned to get definite information on physiological, anatomical and biochemical aspects involved in this malady so that the consequent amelioration strategies may reoriented. In the present investigations, the comparative analysis of wilt affected and healthy plants were carried out over the developmental period and found significant alterations in physiological, anatomical, biochemical characteristics. Complete mortality of wilt affected trees was recorded within six months of symptoms development at all three locations. With the objective of amelioration strategy, CoCl2 with was sprayed at varied concentrations {0: ppm (wilted control), T2: 50 ppm, T3: 100 ppm, T4 :150 ppm and T5: water spray (healthy control)} at three distinct locations (L1, L2, L3). The treatments of CoCl2, resulted stability with respect to biochemical and physiological changes in plants during initial days and plants were able to survive and consequent improvement all the parameters was observed with the onset of spring season and new flush. Among all treatments CoCl2 @ 150 ppm was more effective for increasing leaf area index, leaf density, leaf thickness, ascorbic acid, leaf water content, though the lower concentration of 50 and 100 ppm were found effective. To confirm the pathogenicity in guava wilt disease, two-year-old guava plants, planted in 26-inch cemented pots were subjected to repeated fungal inoculation (Fusarium solani) with and without stem as well as root injuries singly and in combinations. The results revealed that the fungal inoculations in the rootzone of the plants could not affect the plants, whereas, the inoculation along with root and root+stem injury resulted about 90 % mortality of plants, which was again confirmed by isolating the culture from the shoot tips of the plants. Similarly, in our last experiment, 90 experimental trees exhibiting wilt symptoms were tagged and subjected to different treatments to assess the physiological, anatomical, biochemical, nutritional, fruit yield and quality parameters. The observations recorded on 0, 30, 90, 180 and 300 days revealed significant improvement in plant growth and developments after 90 days of application and values rises significantly the end of observation period (180 to 300 days) and plants resumed the growth as normal. Among all treatments, T4 (150 ppm @CoCl2) followed by T3 (100 ppm @ CoCl2) and T2 (50 ppm @ CoCl2) gave promising results for pigment levels, photosynthetic rate, canopy volume, leaf area index, leaf density and root density. Biochemically, maximum improvement in treated trees was recorded after 180 days of treatments. Data on ethylene and auxin exhibited significant rise in the excised leaves of both wilted and healthy plants initially followed by decline after 8 hours, but at faster rate in wilted plants. From the investigations, it may be inferred that the pathogens are not a primary cause of guava wilt disease. The mechanical root injury or other abiotic stress factors acts as a primary cause to makes the plants prone to be attacked by the pathogen infections. Triggered ethylene level and consequent amelioration of wilting plants using ethylene inhibitor corroborated the hypothesis of investigations.
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Studies on nutritional management of greening affected Kinnow mandarin plants
(Punjab Agricultural University, Ludhiana, 2022) Kudrat Preet Kaur; Sangwan, Anil Kumar
The present investigation was carried out at Dr J C Bakhshi, Regional Research Station, Abohar during the year 2020-21. It was aimed to investigate the influence of spraying zinc and manganese solutions on 13-year-old Kinnow mandarin plants that were affected by the greening disease. The experimental design was a randomized block with 3 plants per treatment (nutrition) subdivided into replicates. Different treatments of varying doses of zinc and manganese alone or in combination were applied. First spray was scheduled for mid august and second dose wherever required (as per treatments) was given during September. Fruits were harvested at maturity and analysed in the laboratory for various quality and physic-chemical parameters in PG, Nutrition Laboratories of Department of Fruit Science, Punjab Agricultural University, Ludhiana, Punjab. In general, it was observed that double sprays of zinc and manganese alone or in combinations were superior over single sprays. In particular, zinc sprays were found to be superior over manganese sprays. However, zinc and manganese together gave a synergistic effect and proved to be better than individual sprays of nutrients. The results indicated that application of zinc and manganese in combination [Zn (0.5%) + Mn (0.5%) (Two Sprays)] gave maximum increment in plant height (15.82 cm), spread and volume (5.26 cubic m) along with highest number of fruits (681.7) and fruit yield (112.71 q/acre). While, treatment T12 [Zn (0.5%) + Mn (0.3%) (Two Sprays)] recorded maximum fruit size, weight (150.7 g) and volume with highest fruit TSS (10.30 oBrix), TSS/ acidity ratio (12.26), pH (4.35), total sugars (6.32%), ascorbic acid (25.1 mg/100ml juice) and phenol content (32.2 mg GAE/g DW) along with minimum acidity (0.84%), showing at par results with treatment T14 [Zn (0.5%) + Mn (0.5%) (Two Sprays)] and the lowest values of these parameters were recorded with control treatment. Whereas, maximum juice percent (50.0%) and minimum peel (24.0%) and rag (26.0%) percent along with peel thickness (1.98 mm) were recorded with treatment T4 [Zn (0.5%) (Two Sprays)].
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Studies on post-harvest behaviour of peach (Prunus persica L. Batsch) under low temperature storage conditions
(Punjab Agricultural University, 2022) Sukhjit Kaur; Jawandha, S.K.
The present investigation entitled ‘Studies on post-harvest behaviour of peach (Prunus persica L. Batsch) under low temperature storage conditions’ was conducted in the Department of Fruit Science, Punjab Agricultural University, Ludhiana during the year 2019 and 2020. In experiment-I, physiological mature and uniform fruits of peach cultivars ‘Flordacrest’, ‘Valley Grande’, ‘Flordagrande’, ‘Tropic Beauty’, ‘Partap’, ‘Early Grande’, ‘Flordaglo’, ‘Tropic Snow’, ‘Tropic Sweet’, ‘Parbhat’, ‘Flordaprince’, ‘Punjab Nectarine’ and ‘Suncoast’ were packed separately in CFB (corrugated fiber board) boxes and stored at 0-1ºC and 90-95% relative humidity for 40 days. In experiment -II, physiological mature and uniform fruits of peach cultivar ‘Shan-i-Punjab’ were dipped in aqueous solutions of sodium nitroprusside (0.50 mM, 1.0 mM & 2.0mM), salicylic acid (0.5 mM, 1.0 mM & 2.0 mM) and ascorbic acid (0.5 mM, 1.0mM & 2.0 mM) for 5min and control fruits dipped in water only. Peach fruits under various treatments were packed separately in CFB boxes and stored at 0-1ºC and 90-95% relative humidity for 40 days. In experiment -III, physiological mature and uniform fruits of peach cultivar ‘Shan-i-Punjab’ were coated with different edible surface coatings of beeswax (0.50 %, 1.0 % & 2.0 %), chitosan (0.25 %, 0.50% & 1.0%) and sodium alginate (0.50 %, 1.0 % & 2.0 %) and control fruits were kept uncoated . These coated and uncoated peach fruits were shade dried and packed separately in CFB boxes and stored at 0-1ºC and 90-95% relative humidity for 40 days. Both treated and untreated cold stored peach fruits of all these three experiments were analyzed for different physico-chemical attributes and enzymatic assays on 0,10th, 20th, 30th and 40th day of storage. Results revealed that fruits of peach cultivar ‘Flordacrest’ registered longer postharvest life with acceptable fruit quality upto 30 days under low temperature storage conditions. Peach fruits cultivar ‘Shan-i-Punjab’ treated with sodium nitroprusside 1.0 mM (experiment-II) and beeswax 2.0%(experiment-III) coating delayed the ripening process and preserved the fruit quality attributes up to 30 days of cold storage period. Fruits from these both treatments registered the lowest weight loss, spoilage and retained higher fruit firmness, sensory quality, total soluble solids, sugars, titratable acidity, vitamin C, total carotenoids, total phenolics content and total antioxidant activity under low temperature storage conditions. Alongwith this, these treatments (sodium nitroprusside 1.0 mM ; beeswax 2.0% coating) to peach cultivar ‘Shan-i-Punjab’ fruits also delayed the polyphenol oxidase, pectin methylesterase, polygalacturonase & cellulase enzyme activities during cold storage period.
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Studies on physico-chemical and antioxidant properties of lime and lemon during fruit development
(Punjab Agricultural University, 2022) Chauhan, Kriti; Jawandha, S.K.
The present studies were conducted at Fruit Research Farm, Department of Fruit Science, Punjab Agricultural University, Ludhiana during the year 2021-22 on four lime and lemon varieties viz. Baramasi Lemon, Tahiti Lime, Galgal and Sweet Lime. The fruit and leaf samples of Lime and Lemon cultivars were collected from 30 days after fruit set till commercial harvesting at 30 days intervals starting from the month of April. The physicochemical parameters like fruit size, weight, juice content, seed size, moisture content, TSS, TSS/acid ratio, carotenoids and sugars were recorded maximum at final stage of harvesting. Titratable acidity, vitamin C and peel thickness exhibited a declining trend from first to final stage of fruit harvesting. In all four varieties of lime and lemon peel contained greater antioxidant activity, total phenolic content, hydroxyl ion free radical scavenging activity and total flavonoid content as compared to pulp of fruits. In peel and pulp, antioxidant activity declined during fruit development. Limonin was recorded highest in seeds followed by peel and pulp irrespective of stages of development. Sweet Lime was found the most suitable cultivar for table as well as medicinal purposes due to higher level of TSS, sugars, antioxidants, flavonoids and vitamin C content. However, fruits of Baramasi lemon, Galgal and Tahiti Lime are also good sources of different types of antioxidants at initial stages of development. In terms of mineral nutrition leaves contained higher concentrations of nutrients followed by peel and pulp exhibiting a distinct pattern during fruit growth and development.
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Effect of harvest dates and packaging on storage of pear cv. patharnakh
(Punjab Agricultural University, 2022) Sandeep Kaur; Gill, Mandeep Singh
The investigations on the "Effect of harvest dates and packaging on storage of pear cv. Pathernakh." was conducted in Post harvest Laboratory, Department of Fruit Science, Punjab Agricultural University, Ludhiana during 2021. The two factors affecting the storage of pear i.e harvest dates and packaging materials were studied independently. For 1st experiment pear fruits cv. Patharnakh harvested on four different dates (2nd, 3rd, 4th week of July and 1st week of August) and packaged in CFB boxes and stored under cold temperature conditions (0-1 ºC and 90-95 % RH). The observations for various quality attributes were recorded on the day of storage and at 30th, 45th, 60th and 70th days of storage. Results demonstrated that fruits harvested on 2nd week of July consistently exhibited the highest fruit firmness, titratable acidity, total antioxidant activity (TAA) and total phenolics content (TPC) than the late harvested fruits. Contrarily, delayed harvested fruits recorded higher total soluble solids (TSS) and total sugars. Moreover, fruits harvested in 3rd week of July had minimum the weight loss and highest sensory quality until 70th day of storage. The fruit harvested at later harvesting stage recorded higher activities of fruit softening enzymes activities like pectin methylesterase (PME), polygalacturonase (PG) and cellulase enzymes as compared to fruit harvested at earlier stage. Thus, the results revealed that fruits harvested during 3rd week of July had retained all the physico-chemical characteristics and enhanced the storage and keeping quality of pear. On the other hand, packaging methods could have a significant effect on quality and storage life of pear fruits. Hence, this second experiment was conducted to study the effects of different packaging materials on storage quality of Patharnakh pear fruit. The fruit were packed in corrugated fibre board (CFB) boxes, shrink film, cling film and wooden boxes and placed under low temperature storage conditions (0-1 ºC and 90-95 % RH). Physico-chemical parameters and enzymatic activities were conducted on the day of harvest and at 30th, 45th, 60th and 70th days of storage. Results revealed that both film packaging‟s significantly reduced the weight loss and maintained higher fruit firmness throughout the storage period, but showed higher spoilage at the end of storage. However, the fruits packed in CFB boxes exhibited lower spoilage and maintained higher sensory quality, total soluble solids (TSS) and total phenolics content (TPC) at the end of storage. Throughout the storage period, film packaging treatments resulted in higher fruit firmness, acid content, total antioxidant activity (TAA) and lower activities of fruit softening enzymes like pectin methylesterase (PME), polygalacturonase (PG) and cellulase. The results showed that for long term storage of pear fruits CFB box packaging is appropriate method because of higher sensory quality and lower spoilage.

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