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The aim of this study was to determine the effect of different K fertilizers and different K doses on yield and N, P, K content of leaves in grapes. The treatments were the control; 1 %, 2% and 3% KNO3;.and 1% KH2PO4 + NH4H2PO4 foliar applications which were realized weekly at full blossom and ripening. Yield of the grape was regularly recorded for two years. The findings of the investigation are as follows: 1. The effect of KNO3 applications on leaves were found to be significant on fruit yield. The highest yield was obtained at 3 % doses. In 1996-1997 years, KNO3 applications increased fruit yield compared to control plot 35 % and 17 % as a respectively.2. KH2 PO4 and NH4H2PO4 applications increased the yield according to control plot 34% in 1996 and 5 % in 1997 year. 3. It was found that the effect of KNO3 applications was significant on K content of petiol and P, K content of blade. [ABSTRACT FROM AUTHOR]

Due to high pH and calcareousness of soil, the availability of micronutrients is affected (Talibudeed, 1981; Marschner, 1995) and growing citrus on such soils frequently shows deficiency symptoms like yellowing of young growth, interveinal chlorosis and dieback of branches. These are typical symptoms of iron (Fe) and zinc (Zn) deficiencies. Some short duration studies were conducted on micronutrients indicating their response specifically to Zn (Khattak, 1994; Siddique et al. 1994). The soil conditions are such that applied nutrients may not give immediate impact on yield in perennial plants like citrus due to their limited root system and hairs on roots absorbing nutrients from surface soil (Cohen, 19976). Moreover, impact of environmental factors is more affective on fruit plants as compared to field crops due to many reasons not mentioned here. Keeping in view the existing status of information and importance of citrus fruits in Pakistan, a long-term study regarding micronutrient effects on fruit yield is planned and two methods of nutrient application are tested in two separate experiments in farmers' Mandarin. Up to the end of 2004, two years fruit-yield data have been taken. [ABSTRACT FROM AUTHOR]

Partial rootzone drying (PRD) PRD is an irrigation system that may improve the water use efficiency of crop production by means of better control of vegetative growth without reducing fruit yield (Kang and Zhang 2004). PRD uses biochemical response of plants to water stress to achieve a balance between vegetative and reproductive development (Davies and Hartung 2004). However, the underlying nature of how PRD affects berry ripening is only poorly defined, as indicated by the considerable controversy in the literature (Du Toit et al. 2003, Santos et al. 2003, Gu et al. 2004). This may be due to either poor implementation of PRD, or the interaction of many factors on grapevine growth and reproductive development. Given such ambiguities, it becomes necessary to design a PRD system that permits a fine control of most environmental factors with the aim to know the nature of PRD response of plants. Therefore, we have developed a method which uses fruiting cuttings subjected to PRD irrigation under controlled conditions. Emphasis is placed on physiological aspects including berry hormonal balance related to long-distance chemical signalling induced by soil drying. [ABSTRACT FROM AUTHOR]

Quantification of tomato's fruit-sets depends on the level of competition for assimilate in different environment, and this paper presented some results of fruit yield and quality (fruit size) in response to environment (mainly respect to and planting-density and light). Some experiments had been carried out to find the relationship between growth rules of tomato and plant densities A structural-functional model GREENLAB has been developed to simulate it. The results show that increasing plant density results in an increment of biomass production on a ground area but in a reduction of single plant fresh weight. To find rules between organ sink and source relationship, calibrations Environmental conditions were introduced into the model checking the influence on Q/D over plant growth period and fruit set ratio. It is found that changing the Q/D ratio in some critical periods can be used to optimize fruit set and yield of greenhouse tomato. [ABSTRACT FROM AUTHOR]

Historical accounts of possible B roles in the protection of tree and horticulture species against frost damage were reported as early as 1950s, with more field observations and experimental evidence since then. Although the initial reports (Anon 1958; Beltram 1958) were no more than anecdotal evidence due to the lack of proper comparative control experiments, later field and glasshouse studies have provided more reliable evidence about the involvement of B in the protection against frost damage - decreased frost-induced shoot-tip dieback or increased flowering and fruit yield, for example: in subtropical eucalypts Eucalyptus grandis (Cooling 1967; Cooling and Jones 1970) and Eucalyptus grandis x Eucalyptus urophylla (Lu and Huang 2003); apple, pear and blueberry (Blevins et al. 1996; Hanson and Breen 1985; Milovankic et al. 1990) and in birch, Scots pine, and Norway spruce (Braekke 1983). Frost-induced "white top" (bleached young leaves) has been observed in low temperature-sensitive E. urophylla and E. grandis in south China (Xu Daping, pers. comm.) where B deficient soils are common (Dell and Malajczuk 1994). Field observations have also suggested a link between low canopy temperature and enhanced leaf tissue damage (bleached patches) in oilseed rape grown in low B soil in south-east China (Ye et al. 1997). [ABSTRACT FROM AUTHOR]

Citrus is a major world horticultural commodity, and most of its world-wide production depends on irrigation, which is inevitably associated with the deterioration of water quality from run-off or ground water. Citrus, like most fruit trees, is relatively salt sensitive. The deleterious effects of salt stress lead to reduction in fruit yield and quality. In recent years, only a few relatively salt-tolerant rootstocks have been obtained through selection and conventional breeding, due to a rather limited existing genetic pool and the long period of time required for experiments. Attempts to regenerate salt-tolerant citrus plants via in vitro production of salt-tolerant callus or mutagenesis have been rather limited and as of yet not in use. Therefore, efforts should be invested to identify traits/genes that have a key role in tolerance to salt in order to speed up the process and to enlarge these genetic resources QTL analyses revealed that response to salt in citrus is a multigenic trait, as has been shown in other species, but some genes probably exist that have a major impact on salt tolerance and (or) mineral accumulation. Several robust EST databases now exist and are growing, the first microarray chips have been manufactured, and an initial genome sequencing effort is underway. These tools should allow citrus physiologists, biochemists, and geneticists to make much more rapid progress in understanding salt and water stress in the future and to design strategies to ameliorate their effects [ABSTRACT FROM AUTHOR]

Tobacco mosaic virus (TMV) and Tomato mosaic virus (ToMV) cause a serious disease in tomato, with systemic mosaic symptoms and losses in fruit yield and quality. Both viruses are closely related tobamoviruses, plus stranded RNA viruses with a rod like particle structure. The genomic structure of TMV and ToMV has been well characterized, as a positivesense single-stranded RNA genome that encodes at least four proteins (Goelet et al. 1982; Ohno et al. 1984; Canto et al. 2004). The 130 kDa methyltransferase/helicase and the 180 kDa RNA dependent RNA polymerase are translated directly from the genomic RNA using the same first initiation codon, the latter is synthesised by the read-through of the amber termination codon of the 130 kDa protein gene. The movement protein (MP) and the coat protein (CP) are translated from their respective subgenomic mRNAs, which are synthesised during the replication cycle. Involvement of the 130 kDa and 180 kDa proteins in intracellular replication has been demonstrated by deletion or substitution mutants of each protein (Ishikawa et al. 1986). It has also been shown that the MP is involved in cellto-cell transport (Meshi et al. 1987), and that the CP is involved in long-distance movement (Saito et al. 1990; Hilf and Dawson, 1993). In tomato, TMV infection is more or less a rare event because the virus is soon competed out in tomato populations by ToMV, which is more adapted to this host plant. [ABSTRACT FROM AUTHOR]

Pistillate flower abortion (PFA), induced by excessive pollen load on female flowers and leading eventually to their abscission, affects severely fruit set and potential fruit yield in ‘Serr' walnut variety. Such variety, owing to its nut quality, is extensively planted in Chile and in other walnut-producing areas in the world (California). [ABSTRACT FROM AUTHOR]