Water requirements of avocado in Israel. II.* Influence on yield, fruit growth and oil content

1977 ◽  
Vol 28 (5) ◽  
pp. 869 ◽  
Author(s):  
E Lahav ◽  
D Kalmar

The effect of four different irrigation intervals, 7, 14, 21 and 28 days, on the avocado tree was tested during the years 1968–1974 in the northern coastal plain of Israel. The respective average annual water applications were 8890, 7450, 6680 and 5940 m3/ha. The cultivars Ettinger, Fuerte and Hass were tested in five replications in randomized blocks. After 6 years no significant reduction in yield was observed with Ettinger or Fuerte trees irrigated once in 21 or 28 days. With the Hass cultivar the 28-day interval gave lower yields than with the three other intervals tested. Shortening of irrigation intervals increased the growth rate and size of individual fruits, which may be of economic importance for cv. Hass, where overproduction leads to small fruits unsuitable for export. Shortening of irrigation intervals tended to increase the oil percentage of the fruit, which may advance the harvest date. In view of the equal yields obtained and the predominance of cv. Hass in avocado plantations, it was concluded that the 21-day interval was the optimum irrigation frequency under the experimental conditions. __________________ *Part I, Aust. J. Agric. Res., 28: 859 (1977).

1977 ◽  
Vol 28 (5) ◽  
pp. 859 ◽  
Author(s):  
D Kalmar ◽  
E Lahav

The effect of different irrigation intervals on the avocado tree was tested during the years 1968–1974 in the northern coastal plain of Israel. The objectives of this experiment were: (a) to make measurements of soil and plant parameters to help understand mechanisms of response to irrigation; and (b) to establish the most suitable irrigation schedule for highest yields of export quality fruit. The trial consisted of four irrigation treatments, at intervals of 7, 14, 21 and 28 days; the respective average annual water applications were 8890, 7450, 6680, and 5940 m3/ha. The cultivars Ettinger, Fuerte and Hass were tested in five replications in randomized blocks. Soil moisture consumption was estimated by using a neutron probe and tensiometers. Most of the water consumption was from the upper 60-cm soil layer. With the 7-day interval, the calculated daily loss from the soil profile was greater throughout the whole irrigation season than with the other intervals. The least salt accumulation occurred under the long interval treatments since the large amounts of water supplied at each irrigation leached the salts continuously. Reduced intervals between irrigations resulted in increased trunk growth and increased tree size. It is concluded that with a 21-day interval the vegetative growth of producing trees was restricted and therefore relatively smaller trees with easier fruit picking and delayed orchard thinning were obtained.


Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 344
Author(s):  
Md Momtazur Rahman ◽  
Mikhail Vasiliev ◽  
Kamal Alameh

Manipulation of the LED illumination spectrum can enhance plant growth rate and development in grow tents. We report on the identification of the illumination spectrum required to significantly enhance the growth rate of sweet basil (Ocimum basilicum L.) plants in grow tent environments by controlling the LED wavebands illuminating the plants. Since the optimal illumination spectrum depends on the plant type, this work focuses on identifying the illumination spectrum that achieves significant basil biomass improvement compared to improvements reported in prior studies. To be able to optimize the illumination spectrum, several steps must be achieved, namely, understanding plant biology, conducting several trial-and-error experiments, iteratively refining experimental conditions, and undertaking accurate statistical analyses. In this study, basil plants are grown in three grow tents with three LED illumination treatments, namely, only white LED illumination (denoted W*), the combination of red (R) and blue (B) LED illumination (denoted BR*) (relative red (R) and blue (B) intensities are 84% and 16%, respectively) and a combination of red (R), blue (B) and far-red (F) LED illumination (denoted BRF*) (relative red (R), blue (B) and far-red (F) intensities are 79%, 11%, and 10%, respectively). The photosynthetic photon flux density (PPFD) was set at 155 µmol m−2 s−1 for all illumination treatments, and the photoperiod was 20 h per day. Experimental results show that a combination of blue (B), red (R), and far-red (F) LED illumination leads to a one-fold increase in the yield of a sweet basil plant in comparison with only white LED illumination (W*). On the other hand, the use of blue (B) and red (R) LED illumination results in a half-fold increase in plant yield. Understanding the effects of LED illumination spectrum on the growth of plant sweet basil plants through basic horticulture research enables farmers to significantly improve their production yield, thus food security and profitability.


1979 ◽  
Vol 15 (1) ◽  
pp. 65-71
Author(s):  
A. N. Asthana ◽  
S. D. Dube ◽  
P. N. Tiwari ◽  
P. N. Gambhir ◽  
T. S. Rajan

SUMMARYOil content (percentage) was determined by pulsed nuclear magnetic spectrometry to study its variability in rai (Brassica juncea) and yellow sarson (B. campestris). Wide inter-varietal and intra-varietal variability was observed in both crops. Genetic aspects of oil content were also worked out, and single-plant and bulk selection methods used for 3 years to exploit the intra-varietal variability. A positive trend in the improvement of oil percentage was observed in 27 out of 30 varieties, some of which showed significant improvements over their respective unselected stocks. A maximum increment of 7% was observed in variety BR 40 of rai and 6% in variety YSM of yellow sarson.


1977 ◽  
Vol 88 (3) ◽  
pp. 727-729 ◽  
Author(s):  
J. B. Smithson ◽  
H. E. Gridley

SUMMARYThe oil content of a number of introduced and local varieties was determined using three nuclear magnetic resonance oil analysers at different centres and compared with results from conventional solvent extraction. Differences were evident between the three centres and between the techniques but in both cases the rankings were similar.


2006 ◽  
Vol 49 (3) ◽  
pp. 457-461 ◽  
Author(s):  
Marcelo Henrique de Carvalho ◽  
Claudio José Von Zuben

The objective of this work was to evaluate some aspects of the populational ecology of Chrysomya megacephala, analyzing demographic aspects of adults kept under experimental conditions. Cages of C. megacephala adults were prepared with four different larval densities (100, 200, 400 and 800). For each cage, two tables were made: one with demographic parameters for the life expectancy estimate at the initial age (e0), and another with the reproductive rate and average reproduction age estimates. Populational parameters such as the intrinsic growth rate (r) and the finite growth rate (lambda) were calculated as well.


2018 ◽  
Vol 48 (3) ◽  
pp. 197-206 ◽  
Author(s):  
Arlan de Lima PAZ ◽  
Adalberto Luis VAL

ABSTRACT Colossoma macropomum, known locally as tambaqui, is the native fish most farmed in Brazil, however, technological advances are needed to reach efficient production rates. Modulating growth factors, such as growth hormone, may be associated with improved growth rate and feed efficiency. The use of exogenous hormone for fish rearing is prohibited in Brazil, yet the experimental use of bovine hormone can be useful in research aimed at understanding how to stimulate endogenous growth hormones in fish. Therefore, the present study had the strict objective of understanding the effects of growth hormone on the physiology and zootechnical parameters of C. macropomum under experimental conditions. The animals were intraperitoneally injected every fifteen days with 1, 10 and 100 μg g-1 of bGH using 0.9% NaCl saline as diluent. The 10 and 100 μg g-1 bolus had a positive effect on the performance indexes of C. macropomum: weight gain (g), growing length (cm), daily weight gain (g), feed conversion and specific growth rate (% per day). The bGH promoted a greater increase in length than in mass, which caused a reduction in condition factor of the individuals receiving a bolus of 10 and 100 μg g-1. Furthermore, bGH caused no changes in glucose levels, cortisol, hematological parameters, plasma levels of Na+ and K+, and activity of gill’s H+-ATPase and Na+, K+-ATPase, at least during the experimental period considered in the present study.


1977 ◽  
Vol 88 (3) ◽  
pp. 731-736 ◽  
Author(s):  
H. E. Gridley ◽  
J. B. Smithson

SUMMARYDifferences between sites accounted for a large proportion of the variation in the oil percentage of cotton seed from variety and agronomic trials conducted in Northern Nigeria but were not consistent between seasons. Reduced oil percentages from the drier areas of the north and from later sowings suggested that length of season is an important factor but insect attack and differences in the amounts of nitrogen, potash and boron applied to the soil also contributed to the variation. Application of insecticide, potash and boron increased and nitrogen decreased oil percentages. The latter effect usually resulted from an increase in seed size without a corresponding increase in oil content. The variation in the oil percentages of commercial varieties derived from the same Nigerian Allen stock and the relatively small interactions between varieties and environments suggested that this character might be improved by selection.


1996 ◽  
Vol 5 (3) ◽  
pp. 245-252 ◽  
Author(s):  
Kebe Brahim ◽  
David K. Stumpf ◽  
Dennis T. Ray ◽  
David A. Dierig

1996 ◽  
Vol 11 (5) ◽  
pp. 1114-1119 ◽  
Author(s):  
A. Endo ◽  
H. S. Chauhan ◽  
Y. Nakamura ◽  
Y. Shiohara

Y1Ba2Cu307−x (Y123) crystals were grown by two different methods, the constant undercooling solidification and the continual cooling method, with top seeding by Sm123 seed crystals in order to investigate a relationship between undercooling (ΔT) and a growth rate (R). The crystals of Y123 with a sharp faceted interface, which consisted of {100} and {001} faces, grew epitaxially from the seed. It was found that the growth rates of {100} face (Ra) and that of {001} face (Rc) showed an increasing trend with increasing ΔT, and Rc was faster than Ra within these experimental conditions, ΔT < 20 K. The relation between R and ΔT follows the parabolic equation, viz. Ra ∝ ΔT1.9 and Rc ∝ ΔT1.3 for {100} and {001} faces, respectively. The simulated crystal size using the R and ΔT relations obtained from the constant undercooling method showed good agreement with experimental data by the continual cooling.


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