Cumulative Fruit Yield Research Articles

Early rootstock selection under ‘tahiti’ acid lime crown in Capitão Poço, Pará State, Brazil

Citrus represents one of the main fruit crops grown in the world, highlighting the ‘Tahiti’ acid lime tree. The objective was to compare rootstock varieties combined with this scion to identify those with the best agronomic performance and precocity of production, in addition to Phytophthora gummosis resistance. The experiment was carried out in Capitão Poço, northeast region of Pará, and the following seven rootstock genotypes were evaluated: ‘Sunki Tropical’, ‘BRS O S Passos’, ‘BRS Bravo’, ‘BRS Donadio’, ‘Citrandarin Indio’, ‘BRS Matta’, and ‘LVK x LCR-038’. A randomized block experimental design was used, with three replications and 10 plants per plot. The evaluated characteristics were: plant height (m); crown volume (m3); number of ripe fruit per plant; total yield of ripened fruit per plant (kg plant-1); cumulative fruit yield (fruit kg plant-1); and average productive efficiency (fruit kg m-3 of crown). The average productive efficiency was high. For early selection, the best rootstocks in terms of yield, stability and adaptability were Sunki Tropical, BRS O S Passos, and Cintradarin Indio. The fruit number had the greatest direct effect on fruit yield, and crown pruning was directly harmful. Further studies to understand the complex interaction of G x E for BRS Donadio and Sunki Tropical should be carried out.

Long-term field evaluation of Pera sweet orange selections under the Brazilian humid subtropical climate

Currently, a low number of citrus varieties are commercially planted to supply the Brazilian citrus industry demand. The diversification of citrus scion and rootstock varieties is an important strategy to prevent disease outbreaks and to obtain higher off-season profits, as well as to extend fruit supply for the citrus processing industry. The aim of this study was to evaluate 16 Pera sweet orange selections (Citrus ×sinensis Osbeck) under a humid subtropical climate in the northwest region of the state of Paraná, Brazil regarding tree development, production, and disease incidence. The experimental orchard was planted in December 2012 in a randomized block design with three replications and five trees per plot. All scions were grafted on Rangpur lime rootstock (C. ×limonia Osbeck). The evaluations were performed from 2016 through 2022, and included vegetative growth, yield, fruit quality, estimated tree density and productivity for new plantings, and incidence of diseases as citrus canker, huanglongbing (HLB), and citrus tristeza virus (CTV). All data was submitted to ANOVA and means grouped by the Scott Knott’s test (p ≤ 0.05). Pera Perão was the most vigorous variety, with the heaviest and largest fruit, and was among the selections with the highest content of soluble solids (SS), titratable acidity (TA) and juice. However, this variety showed a light-yellow juice color, and one of the lowest SS·TA−1 ratio. This selection had the lowest percentage of fruits with citrus canker but was among the selections with the highest HLB incidence. The selections Ovale, Clone 9, and Clone 42 also showed higher vegetative growth and fruit length, but lower SS content, juice yield and technological indices. All other Pera selections had lower tree height and canopy volume than Ovale, Clone 9, and Clone 42, and adequate overall fruit quality. Conversely, Pera Comprida, Dibbern, Morretes, and Seleç ão 12 scored lower cumulative fruit yield. Pera Pirangi and Comprida had the highest citrus canker incidence on fruits, while Morretes, Ovo, Pirangi, Seleç ão 12, and Seleç ão 27 had the highest HLB incidence alongside Perão. Low severity level of stem pitting was observed within the evaluated selections. The scores ranged from one (absence of stem pitting) to two (sparse surface stem pitting). IAC, Olímpia, Mel, Bianchi, and IPR 159 revealed to be the most suitable for new plantings under humid subtropical edaphoclimatic conditions, as trees had small vegetative growth, high yield performance and fruit quality, in addition to showing lower incidences of citrus canker, HLB and CTV.

Productive performance of ‘Pera’ sweet orange grafted onto 37 rootstocks in tropical cohesive soils under rainfed condition

• Cumulative fruit yield was decisive for identify promising rootstocks to ‘Pera’;. • Rangpur, Volkamer x Rangpur, Maravilha Sunki and Indio induced higher yield to ‘Pera’;. • Florida Sunki x citrange 13–012 and Sunki x Swingle-041 perform similar to Rangpur. • The citrus rootstocks induced no significant change on the fruit's quality. In tropical cohesive soils of Brazil, ‘Rangpur’ lime provide high fruit yield to ‘Pera’ sweet oranges. However, the predominance of a single rootstock puts the citrus industry in this region at risk. To identify promising rootstocks for diversification of ‘Pera’ sweet orange orchard's in the tropical cohesive soils of Brazil, a trial was established with 37 citrus rootstocks on the northeast coast of Brazil. The horticultural performance, fruit yield up to the tenth year, and physic-chemical fruit quality attributes were evaluated. The rootstocks induced changes in the tree size, cumulative fruit yield fresh mass and size of fruit, but had not significant influence on chemical fruit quality. The Hierarchical Cluster Analysis allowed group rootstocks into three classes, in which the accumulated fruit yield was the attribute that most contributed. A group with 15 rootstocks was chosen due to the best productive performance and fruits with 193.75–218.5 g, 57.36–62.65% of juice with 9.85–13.08° brix, which meets the requirement of the Brazilian market. Among these 15, the hybrid of ‘Volkamer’ lemon (VKL) with ‘Rangpur’ lime (RL), ‘Maravilha Sunki’ mandarin, ‘Indio’ citrandarin and the local selection of RL stood out by inducing the highest yield . VKL × RL – 030 produced fruits later, but favored the highest fruit yield at the tenth year. Trees grafted on these four rootstocks and also onto RLCNPMF, TSKC × CTQT1434 – 001, MXWL × LHA – 004, ‘Santa Cruz’ Rangpur, ‘San Diego’ citrandarin,– 004 and trifoliate TRH-208 had greater production regularity across the harvests, although the last three showed lower cumulative yield. The earliest fruit bearing was induced by TSKFL × CTC13 – 012, followed by the ‘Sunki' mandarin hybrids TSKC × CTQT1434 – 001, RL, TSKC x TRFD -007 and TSKC x CTSW-041. It is concluded that the most promising rootstocks for diversification of citrus orchards under rainfed condition on the northeast coast of Brazil are VKL x RL-030, ‘Maravilha Sunki’ , ‘Indio’, TSKFL × CTC13 – 012 and TSKC × CTQT1434 – 001, RLCNPMF – 004, TSKC x TRFD -007, TSKC x CTSW-041 and MXWL × LHA – 004.

Yield and resistance of tomato rootstocks to Meloidogyne arenaria in a greenhouse

Abstract The objective of this work was to evaluate tomato rootstocks with the Mi resistance gene for nematode control and fruit yield, in a greenhouse naturally infested with Meloidogyne arenaria. The experiment was carried out in a randomized complete block design with four treatments (three resistant rootstocks and the Barbaros susceptible cultivar) and four replicates per treatment. 'Barbaros' was grafted onto the 'Arazi', 'Beauford', and 'King Kong' rootstocks, and compared with nongrafted 'Barbaros'. The maximum daily ambient temperatures in the greenhouse was above 28°C, in some days, during the growing period. The grafted tomato had a lower galling index and egg production than the susceptible tomato; however, no significant differences were observed between the three rootstocks. Likewise, there was no difference for the total cumulative fruit yield between rootstocks. All grafted tomatoes also had significantly higher fruit yields than the nongrafted control. The rootstocks provided fruit yields from 40.07% to 63.86% higher than that of the susceptible control in the nematode-infested soil. The rootstocks with the Mi resistance gene favor a higher tomato fruit yields and inhibit the nematode increase in soils infested with M. arenaria.

Leaf proline accumulation and fruit yield of ‘Pera’ sweet orange trees under natural water stress

The water deficit is one of the main limiting factors to the yield of sweet oranges. The present study aimed to determine alternative rootstocks to ‘Rangpur’ lime for ‘Pera’ sweet oranges grown on tropical hardsetting soils with greater potential tolerance to water deficit. Six citrus scion/rootstock combinations were grown during eight years in an orchard established in Sergipe, Brazil. The tree height, number of fruits per plant, cumulated fruit yield, leaf proline content and survival rate of trees were evaluated between 6th and 8th year after planting. Greater rate of tree loss occurred among the sweet orange onto ‘Orlando’ tangelo, which also induced the lowest cumulative fruit yield. After prolonged water deficit, moderate to high proline content was found in trees grafted on Sunki of Florida mandarin × C13 citrange – 012° (TSKFL × CTC13-012), ‘Orlando’ tangelo, ‘Indio’ and ‘Riverside’ citrandarin. Conversely, after a short water deficit during the wet season, trees on ‘San Diego’ citrandarin and Rangpur lime clone of Centro Nacional de Pesquisa Mandioca e Fruticultura – CNPMF 03 ‘Rangpur’ lime showed higher proline content. Trees onto TSKFL × CTC13-012 and ‘Indio’ also induced the greatest accumulated fruit yield at the 8th year after planting. It is assumed that ‘San Diego’ and CNPMF 03 ‘Rangpur’ induce response more quickly to water deficit, whereas TSKFL × CTC13-012 and ‘Indio’ are less susceptible to prolonged deficit. Therefore, trees on ‘San Diego’ and Indio citrandarin, CNPMF-03 ‘Rangpur’ lime, TSKFL × CTC13-012 hybrid present greater potential to tolerate water deficit and produce more fruits on the hardsetting soils of the coastal tablelands of the Brazilian Northeast.

‘Tropical Sunki’ mandarin and hybrid citrus rootstocks under ‘Pera’ sweet orange in cohesive soil and As climate without irrigation

The search for alternative rootstocks to the ‘Rangpur’ lime tree is a challenge to the sustainability of citrus in the Tabuleiros Costeiros (Coastal Tablelands) of Northeastern Brazil. New varieties should meet high drought tolerance with water deficit, cohesive soils, resistance to citrus diseases and inducing high production of fruit. In this work, the performance of ‘Pera’ sweet orange was evaluated on ‘Tropical Sunki’ mandarin and 27 hybrid citrus rootstocks in Umbaúba, Sergipe. A local selection of the ‘Rangpur’ lime was the control. Planting was in 2013 at tree spacing of 6.0 × 3.0 m, without irrigation. Tree size, fruit yield and quality, tree survival rate and graft-compatibility were assessed until 2019. Experimental design was completely randomized blocks with 29 treatments, three replicates and four plants in the plot. Two selection indices were applied to the data to assist in decision making. The ‘Tropical Sunki’ mandarin induced similar cumulative fruit yield in relation to the ‘Rangpur’ lime, suggesting a good drought tolerance of the former rootstock. The TSKC × (LCR × TR) - 073 induced slightly lower productivity, compensated by higher productive efficiency and higher concentration of soluble solids, whereas LCR × TR - 001 and HTR - 166 were highly efficient dwarfing rootstocks. The multiplicative and the rank sum indices showed high correlation, both classifying ‘Tropical Sunki’ mandarin, ‘Santa Cruz Rangpur’ lime, LVK × LCR - 010 and - 038, HTR - 127, in addition to the three aforementioned hybrids, as superior to the local selection of ‘Rangpur’ lime.

Effect of nitrogen and potassium fertigation on growth, yield, quality and nutrient use efficiency of banana under subtropics

A field experiment was conducted during 2016–19 to standardize the fertilizer dose and scheduling for growth, yield and quality of banana under subtropical conditions at Research Farm of ICAR-Central Institute for Subtropical Horticulture, Rehmankhera, Lucknow. The highest mean pseudo stem girth (60.24 cm), leaf area (6.922 m2) and cumulative fruit yield (94.60 t/ha) were recorded in 100% recommended dose of fertilizer (RDF) of N and K applied (40:25, 30:35, 30:25, 0.15) at different phenological stages of growth. Whereas, maximum B:C ratio (2.10) and Total Soluble Solids (21.7 OB) was recorded in 80% RDF of N and K applied (40:25, 30:35, 30:25, 0.15) at different stages of growth. Where as, mean nutrient use efficiency ((41.40 tons fruit/tons nutrient) was recorded in 60% RDF of N and K applied (10:10, 40:20, 30:20, 20:40) at vegetative growth, pre-flowering, flowering and bunch development stage in banana cultivar Grand Naine under subtropical conditions.

Yield performance of apple rootstocks of the Geneva series on replanting soil

Abstract: The objective of this work was to identify rootstocks with competitive agronomic potential to substitute those currently used in Southern Brazil for the Galaxy and Fuji Suprema apple scion cultivars cultivated on replanting soils. The experiment was carried out in the municipality of Lebon Regis, in the state of Santa Catarina, Brazil, from the 2009/2010 to the 2014/2015 crop season, in a randomized complete block design, with four replicates. The yield performance of the 'Galaxy' and 'Fuji Suprema' scions grafted on the G.056, G.202, G.213, G.814, G.896, G.969, M.9, and Marubakaido/M.9 rootstocks was evaluated. G.896 and G.814 stood out due to their superior annual and cumulative fruit yields, as well as to their greater yield regularity, although they showed lower ability of dwarfing the scion. The greatest average fruit weight of 'Galaxy' was obtained on G.056 and G.213. For 'Fuji Suprema', G.969 promoted smaller fruits, whereas the other rootstocks did not differ. All the evaluated rootstocks produced less suckers than Marubakaido/M.9 and less burrknots than M.9 and Marubakaido/M.9. In general, on replanting soil conditions, G.202 is promising among dwarfing rootstocks, mainly for 'Fuji Suprema'. G.056, G.814, and G.896 also stand out, and the two first are more specific for 'Fuji Suprema'.

Harnessing potential yield of mango (Mangifera indica L.) cv. Dashehari by adopting efficient system of planting under Lucknow condition

A field experiment was conducted to evaluate the impact of planting systems on tree canopy volume and fruit yield in mango cv. Dashehari under Lucknow condition. The treatments were comprised of five planting systems viz., square system (100 plants ha-1), hedgerow system (166 plants ha-1), double hedgerow system (222 plants ha-1), cluster system (178 plants ha-1) and paired row system (133 plants ha-1). The experiment was laid out in a randomized block design with four replications. The pooled data from the year 2004-05 to 2012-13 indicated that, vegetative growth in terms of tree canopy volume was found higher under hedge row and double hedge row system of planting. Maximum cumulative fruit yield and also mean yield were obtained in double hedge row system of planting (55.72 and 6.19 t ha-1, respectively).

Evaluation of several dessert cultivars of plum, new under climatic conditions of Poland

An experiment was established in the spring of 2006 in the Experimental Orchard in Dąbrowice (central Poland). The plum cultivars under assessment included: ‘Avalon’, ‘Edda’, ‘Excalibur’, ‘Jubileum’, ‘Mallard’ and ‘Reeves’. Trees of the cv. ‘Victoria’ were the control combination. On the basis of the eight-year study it was found that the most vigorously growing were trees of the cultivar ‘Excalibur’. The most susceptible to frost damage and infection by Chondrostereum purpureum (silver leaf) were trees of the cultivars ‘Edda’ and ‘Excalibur’. In addition, the cv. ‘Excalibur’ was characterized by high susceptibility to the Plum pox virus (sharka). The highest cumulative fruit yield was shown by the cultivar ‘Jubileum’. The worst fruiting were trees of the cultivar ‘Mallard’. Fruits of the cv. ‘Excalibur’ had the highest weight. The smallest were fruits of the cv. ‘Edda’ characterized by early ripening time. The highest amounts of soluble solids were contained in fruits of the cultivar ‘Avalon’. The cvs ‘Edda’, ‘Reeves’ and ‘Avalon’ proved suitable for cultivation in Polish climatic conditions.

Generative developments and pomological traits of apple (Malus x domestica Borkh.) scion cultivars canopy on dwarf clonal rootstocks in dry temperate ecosystem of north-west Himalayas

The investigations were undertaken to study the generative developments of thirteen scion cultivars grafted onto four dwarfing rootstock clones viz., EMLA.111, EMLA.7, MM.111 and BUD.9 for pomological traits in dry temperate ecosystem of north-west Himalaya of India. Comparing scion cultivars after 7 years of planting, the survival was recorded maximum for ‘Gale Gala’ grafted onto EMLA.111 and the poorest for ‘Oregon Spur-II’ grafted onto BUD.9 rootstock clone. EMLA.111 and EMLA.7 performed very well with “Gale Gala” and ‘Golden Spur’ with regard to agro-morphometric traits and elevated yield efficiency. The growth vigor of trees grafted onto EMLA.111 and EMLA.7 was larger than those on BUD.9. After seventh harvest season, the rootstock and scion cultivar significantly affected TCSA, TCV, CA, root suckering, yield efficiency and fruit size. Maximum TCSA, TCA and CA were recorded in scion cultivar grafted onto EMLA.111. The greatest root suckering was developed from EMLA.111 (Gibson Golden) and EMLA.7 (Red Gravenstein, Sparton), and the least in EMLA.111 (Gale Gala). Correlation analysis of different attributes representing the pomological traits also resulted in a significant association at alpha=0.05 attribute pairs. PCA of pomological and fruit quality traits was also worked out to evaluate the differences among scion cultivars tested on different dwarfing rootstock clones. PC4 accounted for 93.9% (pomological traits) and 80.6% (fruit quality) of the cumulative variance of scion cultivars studied. PCA-F1 had the highest positive loadings from plant height, tree girth, TCSA, and TCV followed by PCA-F2 (fruit yield and cumulative fruit yield). Further, no significant differences were obtained when the calculated factor scores of PCA-F1, PCA-F2 and PCA-F3 for fruit quality attributes were analyzed. The study inferred that the ability of the rootstock clones to perform better than current commercial standards, while, promoting orchard health and productivity with enhanced insect-pest and disease resistance.

PRECOCIDADE DE PRODUÇÃO DE CULTIVARES DE MACIEIRA SOBRE DOIS PORTA-ENXERTOS

RESUMO Em ensaios de competição, muitos fatores são avaliados visando a diferenciar as cultivares e a proceder à recomendação de uso. Em relação ao desempenho produtivo, cultivares que entram em produção precocemente, produzem regularmente ao longo dos anos e, ao final, apresentam produções superiores, destacam-se em relação às demais. Desta forma, o trabalho foi realizado com o objetivo de avaliar a precocidade de produção, por meio da aplicação do índice de precocidade de produção, e a produção acumulada de nove cultivares de macieira enxertadas sobre dois porta-enxertos, durante as seis primeiras safras. Os mais elevados índices de precocidade de produção foram exibidos pelas cultivares Daiane, Mishima e Fuji Select no porta-enxerto M-9, e pelas cultivares Fuji Suprema, Daiane e Gala Real no porta-enxerto Marubakaido/M-9. Ao final das seis safras, ‘Baigent’ e ‘Cripps Pink’, no porta-enxerto M-9, e ‘Maxi-Gala’, ‘Baigent’, ‘Daiane’, ‘Gala Real’ e ‘Royal Gala’, no Marubakaido/M-9, apresentaram as maiores produções acumuladas. Somente ‘Daiane’ e ‘Gala Real’, sobre a combinação Marubakaido/M-9, destacaram-se para as variáveis índice de precocidade de produção e produção acumulada, simultaneamente. O índice de precocidade de produção é um parâmetro importante para, junto com outros fatores, como a produção e a qualidade dos frutos, diferenciar cultivares de macieira.

Response of paclobutrazol treatment on flowering, fruit maturity, yield and quality of mango (Mangifera indica) cv Totapuri

A field trial was conducted at Indian Institute of Horticultural Research Bangalore during 2007-2011 to study the effect of different doses and time of application of paclobutrazol on flowering, fruiting behavior and quality of 22 years old mango (Mangifera indica L.) cv Totapuri under South Indian Condition. There were nine treatments involving two doses of paclobutrazol 2.5g and 5.0g a.i/plant with four times of application (last week of July, August, September and October) along with control. All the paclobutrazol applied treatments induced early flowering to an extent by 20- 25 days with increased percentage of flowering of 30-65% compared to control. The harvest maturity was also influenced by paclobutrazol application with an advancement of 3-4 weeks compared to control. The fruit yield was also affected and most pronounced effect was with T5-treatment (2.5g a.i. applied during last week of September) which recorded mean cumulative fruit yield of 141.1 kg/ Plant, which is 55% higher compared to control (91.1 kg/ plant). However, fruit quality attributes such as TSS and acidity were not affected by different dose and time of application of paclobutrazol. Cost benefit ratio was maximum (1:3.02) with the treatment 2.5g a.i. paclobutrazol applied during the last week of September month.

Growth and fruit production of asian pear trees grown on Y-, T-, and vase-training systems

This study was carried out to evaluate the effects of training systems on growth and fruit production of ‘Niitaka’ pear (Pyrus pyrifolia L.) trees in the first 8 years in South Korea. The training systems included Y-trellis (YT), T-trellis (TT), and vase-pergola with either two (VP I) or three main branches (VP II). Tree spacing for YT, TT, VP I, and VP II were 6.5 m between tree rows, and 3.0, 6.0, 3.0, and 6.5 m between trees, respectively. The TT trees had lower tree height, canopy area, and number of new shoots, average length of new shoots, and trunk cross sectional area as compared to those in other training systems in year 3 or year 8. The TT and VP II systems were slow to fill the allotted space from year 3 to 8. The VP I trees had comparatively rapid development of the tree canopy, high cumulative yield efficiency per tree, high cumulative fruit yield per area, and large fruit size, as well as low operation hours for orchard management. Fruit quality parameters, such as fruit shape, soluble solids content, firmness, and titratable acidity, were not consistently affected by training system in years 5 and 8.

Performance of Southern Highbush Blueberry Cultivars Under High Tunnels in Florida

A study was conducted over two southern highbush blueberry (Vaccinium corymbosum × Vaccinium darrowi) seasons in a grower field in Florida. The objective was to compare the early fruit weight of southern highbush blueberry cultivars in high tunnels and in open fields. Four treatments were tested using combinations of two southern highbush blueberry cultivars (Snow Chaser and Springhigh) and two production systems (open fields and 18-ft-high tunnels). The results indicated that there was a significant effect of the production systems on the number of days with air temperatures at or near freezing (≤34 °F), and maximum and minimum air temperatures. The minimum air temperature in open-field plots reached ≈19 and 21 °F (61 freezing or near-freezing events) in the 2009–10 and 2010–11 seasons, respectively, whereas the minimum air temperatures inside the high tunnels were ≈32 and 33 °F, respectively, during the same seasons (only 3 days at ≤34 °F). This indicated that using high tunnels was an effective means to avoid freezing air temperatures in blueberries. In the first season, the cumulative early fruit weight was the highest in plots planted with ‘Snow Chaser’ inside the high tunnels (≈10 tons/acre), while the combined production of the two cultivars in the open fields did not reach 1 ton/acre until the end of the early harvests. The following year, there were no differences in the cumulative early fruit weight of both cultivars when planted in the open fields (2.2 tons/acre) and the cumulative fruit yields of ‘Springhigh’ and ‘Snow Chaser’ growing inside the high tunnels was twice and four times higher, respectively, than the early fruit production obtained in the open fields. These data showed the profound effect of high tunnels on flower protection and fruit set. High tunnels reduced water use for freeze protection. The total volume used in the open fields during the freezing or near-freezing days was ≈2.5 acre-inch/acre per 8 hours of freeze protection, whereas only 1/10 of that volume was applied inside the structures.

Effects of grafting height of MM106 rootstock on growth, lateral shoot formation and yield in apple trees

SummaryBetween 2004 and 2008, the effects of different grafting heights on sylleptic shoots were tested in the apple (Malus domestica Borkh.) cultivars ‘Granny Smith’ and ‘Gloster’, and cumulative fruit yields were evaluated. MM106 apple rootstocks were grafted 10, 20, 40, or 60 cm above soil level in August 2004. The results showed that an increased grafting height significantly decreased tree height in both cultivars. The tallest and shortest trees were observed at grafting heights of 10 cm (153.0 and 170.0 cm) and 60 cm (141.3 and 143.5 cm) in ‘Granny Smith’ and ‘Gloster’, respectively.Among the various grafting heights tested, 60 cm in ‘Granny Smith’ and 20 cm in ‘Gloster’ gave the largest stem diameters (17.6 mm and 16.8 mm, respectively). The number of lateral shoots increased significantly with increased grafting height in both cultivars. The largest numbers of lateral shoots in ‘Granny Smith’ (10.75) and ‘Gloster’ (2.00) were obtained from a grafting height of 60 cm, while 2.55 and zero lateral shoots occurred at 10 cm grafting height in ‘Granny Smith’ and ‘Gloster’, respectively. Shoot lengths decreased significantly by increasing the grafting height. Grafting heights of 10 cm and 60 cm resulted in the tallest and shortest shoots in both cultivars. Cumulative fruit yields were significantly affected by grafting height in both cultivars. The highest yield was found for a 60 cm grafting height in both ‘Granny Smith’ (11.295 kg tree–1) and ‘Gloster’ (4.818 kg tree–1).The results of this study suggest that grafting heights of 40 cm and 60 cm have the potential to promote branching and early bearing for apple fruit production in sustainable and organic agricultural systems.

Studies on Rejuvenation of Old, Unproductive 'Alphonso' Mango Trees in Orchards

A field trial on pruning was conducted from 2004 to 2009 to induce rejuvenation of twenty six year old, unproductive 'Alphonso' mango trees, at Indian Institute of Horticultural Research, Bangalore. In the study, three treatments imposed comprised of two pruning treatments, namely 30cm and 45cm pruning of third order branches from the point of origin, and a control (no pruning). Pruning increased the mean cumulative fruit yield for four years, which was almost double that of control, although the two pruning treatments were on par. Maximum mean cumulative fruit yield (86.3kg/plant) was obtained with 30cm pruning, whereas control treatment recorded a fruit yield of 47.2kg/plant. Fruit quality attributes such as average fruit-weight, TSS, acidity and shelf-life were not affected by the two pruning treatments, for rejuvenation of 'Alphonso' mango.

Autotetraploid trifoliate orange ( Poncirus trifoliata) rootstocks do not impact clementine quality but reduce fruit yields and highly modify rootstock/scion physiology

Two autotetraploid (4×) trifoliate orange ( Poncirus trifoliata (L.) Raf.) rootstocks and the corresponding diploid (2×) rootstocks were compared for their impact on clementine “Commune” ( Citrus clementina Hort. ex Tan) production and on rootstock/scion physiology. Cumulative fruit yield, fruit quality (sugars, organic acids, carotenoids, hesperidin) and scion physiology (stem growth, leaf starch, sugars, chlorophyll content, phenolic content and gas exchange parameters) were investigated. The cumulative fruit yield over 11 years was lower in 4× rootstock/clementine associations and correlated with reduced vigor of the clementine scion. Fruit quality criteria were not affected by the ploidy level of the rootstocks, with the exception of hesperidin content, which was higher with 4× than 2× rootstock/clementine associations. Leaf chlorophyll and phenolic contents were higher with 4× than 2× rootstock/clementine associations. In leaves, the rate of photosynthesis and stomatal conductance was much higher with 2× rootstocks; however, the maximum electron transport rate was lower when compared to the 4× rootstocks. Similarly, leaf starch and sugar contents were much higher with 4× than 2×. Taken together, these results demonstrate that the use of 4× rootstocks dramatically changes both tree physiology and fruit yield, without promoting large changes in fruit quality criteria.

Root zone soil nitrogen management to maintain high tomato yields and minimum nitrogen losses to the environment

Greenhouse field experiments on tomato were carried out at Shouguang, Shandong province, over four double cropping seasons between 2004 and 2008 in order to understand the effects of manipulating root zone N management (RN) on fruit yields, N savings and N losses under conventional furrow irrigation. About 72% of the chemical N fertilizer used in conventional treatment (CN) inputs could be saved using the RN treatment without loss of yield. The cumulative fruit yields were significantly higher in the RN treatment than in the CN treatment. Average seasonal N from irrigation water (118 kg N ha −1), about 59% of shoot N uptake, was the main nitrogen source in treatments with organic manure application (MN) and without organic manure or nitrogen fertilizer (NN). N losses in the RN treatment were lowered by 54% compared with the CN treatment. Lower N losses were found in the MN and NN treatments due to excessive inputs of organic manure and fruit yields were consequently substantially affected in the NN treatment. The critical threshold of N min supply level in the root zone (0–30 cm) should be around 150 kg N ha −1 for sustainable production. April to May in the winter–spring season and September to October in the autumn–winter season are the critical periods for root zone N manipulation during crop growth. However, control of organic manure inputs is another key factor to further reduce surplus N in the future.

Biopharmaceutical Protein Production under Controlled Environments: Growth, Development, and Vaccine Productivity of Transgenic Tomato Plants Grown Hydroponically in a Greenhouse

Biopharmaceutical protein production is a new application of plant biotechnology. Nevertheless, there is limited information for potential protein productivity in commercial production operation. The objective of this study was to characterize the growth and development as well as fruit and protein productivities of transgenic tomato (Solanum lycopersicum) plants in comparison with two nontransgenic reference cultivars under greenhouse conditions with commercially adopted cultural practice. Transgenic tomatoes expressing a predominant antigen fusion protein, F1-V, against plague were used as a model system. Three types of tomatoes were grown for this study: 1) a transgenic T2 line, ‘F1-V’; 2) the background wild-type cultivar, TA234; and 3) a commercial greenhouse cultivar well adopted in North America, Durinta. All plants were grown hydroponically in a greenhouse equipped with heating and evaporative cooling systems for 24 to 30 weeks. When comparing ‘F1-V’ with ‘TA234’, there were no significant differences in growth, cumulative fruit yield, fruit total soluble protein (TSP) concentration, nor cumulative TSP production between the two genotypes. Although there was a difference in plant leaf morphology, this suggests that the transformation event did not affect the key traits of biopharmaceutical protein production. When comparing ‘F1-V’ with ‘Durinta’, ‘Durinta’ yielded more fruit than did ‘F1-V’, although final vegetative biomass of the two genotypes was not significantly different. Cumulative fruit yield per plant of ‘Durinta’ for 13 weeks of harvest was almost twice that of ‘F1-V’. However, TSP concentration of fruits of ‘Durinta’ was only 12% to 34% of that of ‘F1-V’, making the estimated cumulative TSP production by fruits approximately half that of ‘Durinta’. Our results suggest that biomass productivity is not necessarily the high-priority trait in selecting cultivars for high-value protein production and that protein concentration of fruits may be an important factor.