Plant Fruit Yield Research Articles

Application of Systematic Variation Method for Optimizing Mineral Nutrition of Soilless‐Grown Zucchini Squash

Zucchini plants (Cucurbita pepo L.) were grown in perlite bags under greenhouse conditions in 2000 and 2001 at Viterbo Experimental Farm, Central Italy. In a 2000 greenhouse experiment, treatments were six formulations with different ratios of NO3 −, SO4 2−, PO4 3−, K+, Ca2+, and Mg2+ × two total nutrient levels (0.5 and 1 eq plant−1). An unfertilized treatment was also tested. Each nutrient ratio treatment was defined by a high proportion of one nutrient and a low proportion of other ions of equal charge with the same anion:cation ratio and total concentration. The 2000 data of fruit yield and total dry weight biomass were used to calibrate the mathematical model (according to the systematic variation method) relating fruit yield and total dry weight biomass to nutrient proportions and total nutrient levels of the fertilizer and total nutrition. For both fruit yield and total plant biomass, the optimal proportions of macronutrients in the fertilizer and total nutrition were largely composed by NO3 −, K+, Ca2+, and Mg2+ (average 82% of total macronutrients), while the mean optimal total concentration was 2.89 eq plant−1. A verification of the calibrated model against 2001 experimental data showed that the model was able to predict fruit yield and total plant biomass by varying nutrient composition of the medium.

Plant Density and Inter-row Polyethylene Mulch Treatment Affect Growth and Yield of Tomato

A field study was conducted to compare the effect of different planting densities and polyethylene mulch treatments on growth and yield of `Mountain Fresh' trellised tomato grown on raised beds on 1.8-m centers. The experiment design was a split plot with four replications and four mulch treatments as main effects: 1) standard black mulch (B), 2) Sonoco red mulch (R), 3) black mulch with interrow (between beds) reflective white on black mulch (B/W), and 4) red mulch with inter-row R/W. Subtreatments were three within-row spacings: 1) 0.60 m (8966 plants/ha); 2) 0.45 m (11955 plants/ha; standard spacing), and 3) 0.30 m (17932 plants/ha). Yield was determined from eight-plant plots and adjacent plants were harvested at regular intervals to determine plant biomass accumulation and partitioning of biomass among roots, stems, leaves, and reproductive organs. There was a linear increase in yield among mulch treatments with increasing plant density. The B/W mulch treatment increased midseason and total yields ≈20% over that of the other mulch treatments. Fruit yield of plants with the B/W mulch treatment at the 0.3-m spacing was 54% higher (151 MT/ha) than that of plants grown on black mulch with the standard plant spacing of 0.45 m (97.9 MT/ha). There was a linear decrease in fruit size with increasing plant density; however, plants grown at the 0.30-m spacing on the B/W mulched plots exhibited only a 2.7% decrease in fruit size as compared to plants grown at the standard 0.45-m spacing on black mulch.

Foliar Spraying with Zineb Increases Fruit Productivity and Alleviates Oxidative Stress in Two Tomato Cultivars

The effects of foliar spraying of the dithiocarbamate zineb on two cultivars of tomato grown in the field in a site with high ozone concentrations were studied by means of biomass assessment, antioxidant enzyme assays, lipid peroxidation, and chlorophyll fluorescence measurements. Zineb prevented the peroxidation of membrane lipids and decreased the activity of scavenging enzymes, which suggests that plants sprayed with zineb are subjected to lower oxidative stress than controls. The beneficial effects of zineb protection is the utilization of a larger fraction of absorbed radiant energy in photosynthesis and a larger fruit yield in plants of both cultivars.

Growth and Yield of Eggplants Grafted by a Newly Developed Robot

Eggplant (Solanum melongena L.) at the two-leaf stage were grafted on scarlet eggplant (Solanum integrifolium Poir.) by hand or a newly developed robot. The scion and rootstock were fixed with an elastic tube for hand grafting or with an adhesive and a hardener for robotic grafting. After acclimatization, the grafted plants were planted at the three- or 11-leaf stage in a glasshouse. Plants grafted by the robot showed a higher percentage of survival, and attained the three- and 11-leaf stages 8 days earlier on average than those grafted by hand. Stems were longer, and shoot fresh mass and fruit yield of plants were higher for the three-leaf-than for the 11-leaf-stage planting, irrespective of the grafting method. Such vigorous growth and high yield by robotic grafting were absent for the 11-leaf-stage planting but obvious for the three-leaf-stage planting.

YIELD RESPONSE OF `SUNRISE' PAPAYA (CARICA PAPAYA) TO KINETIN AND FOLCYSTEINE APPLICATIONS

Field experiments were conducted in the Dominican Republic to determine the effects of different rates of the biostimulants folcysteine and kinetin on fruit yield of `Sunrise' papaya. Aqueous solutions of either 50, 70, 90, 110, or 130 ppm. Four applications were made at 3-week intervals. Fruit number, size, and weight were recorded weekly during 15 weeks after application. Yields for the control and kinetin-treated plants were not significantly different. Significant yield increase was found in plants treated with 70 and 90 ppm of folcysteine solution. Fruit yield in plants treated with 30, 50, 110, or 130 ppm of folcysteine did not differ significantly from that of the control. These results indicate that folcysteine treatment at 70 and 90 ppm at flowering can significantly increase fruit yield in `Sunrise' papaya.

Influence of Mulching Systems on Yield and Quality of Southern Highbush Blueberries

ABSTRACT The effects of four mulching systems (pine bark, black woven fabric, black plastic, white-over-black plastic) on plant growth yield and fruit quality of five southern highbush blueberry clones were studied. Plant growth and fruit yields of plants grown on pine bark or white-over-black plastic were not different and were significantly higher than growth and yield of plants grown on the black mulches. The mulching systems did not significantly affect berry weight, soluble solids, titratable acidity, soluble solids/acid ratio, an-thocyanins, skin firmness or subjective quality after three weeks of refrigerated storage. There were significant effects of clone on each of these parameters.

Micropropagated ‘Redwing’ Raspberry Plants Mulched with Recycled Newspaper Produce Greater Yields Than Those Grown with Black Polyethylene

Abstract Micropropagated ‘Redwing’ (Rubus ideausL. var. idaeus)plants were grown with various mulch treatments to determine the influence of treatments on vegetative growth and fruit yield. Treatments included shredded hardwood bark mulch, degrad-able black polyethylene, sawdust, wheat straw, ground newspaper, shredded newspaper, or ground + shredded newspaper, and a non-mulched control. During the year of establishment, high soil and air temperatures near the surface of the black polyethylene most likely reduced plant survival. The following year, vegetative growth and fruit yield of plants that were previously mulched with black polyethylene were also reduced. Plants mulched with bark, sawdust, straw, and newspaper had greater yield than those mulched with black polyethylene or the non-mulched control. Although yields were similar among plants in all newspaper mulch treatments, ground newspaper was lost under windy conditions and tended to mat down after rainfall, resulting in soggy soil conditions.

Recycled Newspaper: An Effective Mulch for Micropropagated Raspberry Transplants

Micropropagated `Redwing' raspberry plants were grown with various mulch treatments to determine their influence on vegetative growth and fruit yield. Treatments included shredded hardwood bark mulch; degradable black plastic; sawdust; wheat straw; ground, shredded, or ground + shredded newspaper; and an unmulched control. During the year of establishment, high soil and air temperatures near the surface of the black plastic most likely reduced plant survival. The following year, vegetative growth and fruit yield of plants that were previously mulched with black plastic were also reduced. Plants mulched with bark, sawdust, straw, and all newspaper treatments had greater yields than those established with black plastic or in the unmulched control plots. Although yields were similar among plants in all newspaper mulch treatments, ground newspaper was lost under windy conditions and tended to mat down after rainfall, resulting in soggy soil conditions.

Relative Performance of Strawberry Genotypes on Fumigated and Nonfumigated Soils

Performance characteristics for 12 strawberry genotypes (Fragaria ×ananassa Duch.) from the Univ. of California, Davis, strawberry improvement program were evaluated in annual hill culture, with and without preplant soil fumigation using a mixture of 67 methyl bromide:33 chloropicrin (trichloronitromethane) (wt/wt, 392 kg·ha-1). Plants were established at two locations; one trial followed several cycles of strawberry plantation, whereas the other had not been cropped with strawberries for 20 years. Plant mortality was <3% and did not differ between soil treatments; thus, the main effects of fumigation treatment in these experiments were due to sublethal effects of soil organisms. Plants grown in nonfumigated soil produced 51% and 57% of the fruit yield of plants grown in fumigated soil for soils with and without a recent history of strawberry cultivation, respectively. Nonfumigated treatments also had reduced fruit weight and uniformly lower vegetative vigor during the early phases of plantation establishment. Significant genotype x fumigation interactions were not detected for any of the growth or performance traits at either location. Further, the proportion of variance attributable to interactions was at most 25% of that due to variation among genotypes, even for this highly selected population. Genotypic correlations for traits evaluated in different fumigation treatments ranged from 0.80 to 1.00; thus, selection in either soil environment is expected to affect largely the same sets of genes. These results demonstrate that strawberry productivity is substantially increased by fumigation, even in the absence of lethal pathogens or a discernible replant problem. More importantly, there appears to be little opportunity for developing cultivars specifically adapted to sublethal effects of nonfumigated soils.

DEBLOSSOMING IN EARLY SEASON AS IT AFFECTS YIELD DISTRIBUTION OF JUNEBEARING STRAWBERRY IN A SUBTROPICAL CLIMATE GREENHOUSE

Blossom removal of “Douglas” strawberry for the first two weeks of flowering, was studied as to its effect on fruit yield of plants grown inside a greenhouse located in a subtropical climate. Deblossoming resulted in a slightly lower early yield than undeblossomed plants. From the fourth till the ninth week of harvest, deblossomed plants slightly outyielded undeblossomed plants. Yield became similar among both treatments from the tenth week till the last week of harvest (week 17). Weekly and total yields were not significantly different (P> 0.05) among the treatments. Deblossomed plants yielded 29.5 kg/10m2, whereas undeblossomed plants yielded 28.2 kg/10m2, during the harvest period. Since these plants are grown for one season in the greenhouse, from November till June after which they are dug out, there will be no future carry over effect of deblossoming on these plants. Furthermore, the highest economical returns are from the first weeks of harvest, hence, any treatment which reduces early yield in return for a higher later yield, has to be weighed against the higher economical returns of the lower but earlier yield.

Effects of low doses of gamma radiation on the growth and yield of two varieties of tomato

Seeds and 12-day old seedlings of both tall and dwarf varieties of tomato ( Lycopersicon esculentum ) were exposed to gamma radiation (250–2000 R) from a 137 Cs source and then grown under greenhouse conditions. Doses between 500 and 1000 R caused a significant increase in the weight of fruit yield of the two varieties. On the whole, the tall variety showed a greater degree of sensitivity to gamma radiation than did the dwarf variety. Irradiating dry seeds of the tall variety with doses of 250–1000 R caused early ripening of fruits manifested by pronounced increases in the number and weight of ripe fruits over the controls. The effect of radiation on the dry weight of 6-week old plants and the oxygen uptake by germinating seeds was similar to the response of fruit yield of plants derived from irradiated seeds.

UTILIZATION OF CONVENTIONAL AND NON-CONVENTIONAL ORGANIC SOURCES AND INDUSTRIAL BY-PRODUCTS FOR YIELD MAXIMIZATION OF BRINJAL IN COASTAL SOIL

This study was conducted to evaluate the response of brinjal (Solanum melongena L.) with conventional, non-conventional organic source, industrial by-products combined with inorganic fertilizers. The treatments imposed were T1 – Control (100% RDF), T2-100% RDF + Municipal Solid Waste Compost @ 5 t ha-1, T3 – 100% RDF + Municipal Solid Waste Compost @ 10 t ha-1, T­4 – 100% RDF + Vermicompost @ 2.5 t ha-1, T5 – 100% RDF + Vermicompost @ 5 t ha-1, T6 – 100% RDF + Rice Husk Ash @ 5 t ha-1, T7 – 100% RDF + Rice Husk Ash @ 10 t ha-1, T8 – 100% RDF + Lignite Fly Ash @ 5 t ha-1, T9 – 100% RDF + Lignite Fly Ash @ 10 t ha-1. There were nine treatments combinations replicated thrice in CRD. The soil was sandy in texture with available nitrogen, phosphorus and potassium of 257, 10.2 and 117 kg ha-1 respectively which fell in fertility status of low. The soil classified taxonomically as Typic Udisamments. The results showed that application of 100% RDF + Vermicompost @ 5 t ha-1 (T5) significantly increased yield attributes viz., fruit length (16.6 cm), fruit girth (15.2 cm), no. of fruits plant-1 (20.67), fruit weight (45.2 g) and fruit yield plant-1 (934.2 g plant-1). This treatment registered maximum quality attributes like ascorbic acid content (4.5 mg 100 g-1), crude protein (4.81%), drymatter of fruit (70.2 g plant-1) and dry matter of plant (81.3 g plant-1). The post harvest soil available N (148mgkg-1) and P (7.15mgkg-1)status was higher due to application of 100% RDF with Vermicompst @ 5 t ha-1 (T5). The post harvest available K (75.58mgkg-1) status recorded higher in the treatment T9 which received 100% RDF with Lignite Fly Ash @ 10 t ha-1 (T9).