Improved methods for predicting individual leaf area and leaf senescence in maize (Zea mays)

1998 ◽  
Vol 49 (2) ◽  
pp. 249 ◽  
Author(s):  
C. J. Birch ◽  
G. L. Hammer ◽  
K. G. Rickert

The ability to predict leaf area and leaf area index is crucial in crop simulation models that predict crop growth and yield. Previous studies have shown existing methods of predicting leaf area to be inadequate when applied to a broad range of cultivars with different numbers of leaves. The objectives of the study were to (i) develop generalised methods of modelling individual and total plant leaf area, and leaf senescence, that do not require constants that are specific to environments and/or genotypes, (ii) re-examine the base, optimum, and maximum temperatures for calculation of thermal time for leaf senescence, and (iii) assess the method of calculation of individual leaf area from leaf length and leaf width in experimental work. Five cultivars of maize differing widely in maturity and adaptation were planted in October 1994 in south-eastern Queensland, and grown under non-limiting conditions of water and plant nutrient supplies. Additional data for maize plants with low total leaf number (12-17) grown at Katumani Research Centre, Kenya, were included to extend the range in the total leaf number per plant. The equation for the modified (slightly skewed) bell curve could be generalised for modelling individual leaf area, as all coefficients in it were related to total leaf number. Use of coefficients for individual genotypes can be avoided, and individual and total plant leaf area can be calculated from total leaf number. A single, logistic equation, relying on maximum plant leaf area and thermal time from emergence, was developed to predict leaf senescence. The base, optimum, and maximum temperatures for calculation of thermal time for leaf senescence were 8, 34, and 40ºC, and apply for the whole crop-cycle when used in modelling of leaf senescence. Thus, the modelling of leaf production and senescence is simplified, improved, and generalised. Consequently, the modelling of leaf area index (LAI) and variables that rely on LAI will be improved. For experimental purposes, we found that the calculation of leaf area from leaf length and leaf width remains appropriate, though the relationship differed slightly from previously published equations.

2012 ◽  
Vol 5 (1) ◽  
pp. 309-318 ◽  
Author(s):  
MI Kabir ◽  
MG Mortuza ◽  
MO Islam

The experiment was conducted to see the effect of nutrient spray on morphophysiological feature and growth of three orchid varieties namely Dendrobium Red Bull, D. Kasim Gold and D White 5 N. Results revealed that the morphophysiological and growth attributes significantly varied among the cultivars. D Red Bull showed the highest plant height, leaf length, leaf area and stem diameter among the varieties. D. White 5 N was superior in leaf number and total leaf area and D. Kasim Gold was superior in leaf area index and leaf width to the other varieties. On the other hand, the trend of increasing in leaf length, leaf width, leaf area index, leaf number, leaf area and total leaf area was the highest for N:P:K as 10:25:30. Plant height and stem diameter was maximum for N:P:K as 15:20:20. In conclusion, low level of nitrogen and high level of phosphorus and potassium was suitable for leaf length, leaf width, leaf area index, leaf number, leaf area and total leaf area while high level of nitrogen and low level of potassium was suitable for plant height and stem diameter. DOI: http://dx.doi.org/10.3329/jesnr.v5i1.11598 J. Environ. Sci. & Natural Resources, 5(1): 309-318, 2012


2015 ◽  
Vol 50 (1) ◽  
pp. 47-52
Author(s):  
KK Paul ◽  
MA Bari

Plant height, leaf length, leaf breadth, leaf number, leaf area index, corm length, corm breadth, corm weight, sucker number exhibited positive correlation with yield per plant in both genotypic and phenotypic level in cocoyam (Xanthosoma sagittifolium). Path coefficient analysis revealed that leaf length, leaf number, corm length exhibited direct influences to yield per plant. In genotypic level yield per plant showed the highest positive direct effect with corm length followed by cormel breadth, sucker number.Bangladesh J. Sci. Ind. Res. 50(1), 47-52, 2015


2021 ◽  
Vol 30 (1) ◽  
pp. 79-86
Author(s):  
S Rahman ◽  
KN Nishi ◽  
M Muslim ◽  
MK Rahman

A pot (7 kg soil/pot) experiment was carried out to evaluate the growth performance of malabar nut (Justicia adhatoda L.) as influenced by different organic manures. Manures were (a) ACI, (b) FDA, (c) GTS, (d) Green life, (e) Kaji, (f) Majim, (g) Shebok, (h) Shufola, (i) Cowdung, and (j) Water hyacinth, applied at the rate of 10 ton/ha. There were eleven treatments and three replications. Pots were arranged in a completely randomized design (CRD). To evaluate the growth performance viz. height, leaf number, leaf area, and leaf area index, girth, and branches were recorded at 15 d intervals up to harvest. Plants (90 d old) were harvested as root, stem, and leaf. Fresh and dry weights of root, stem, and leaf were recorded. The highest height (80.90 cm), leaf number (28.70 no./plant), leaf area (175.77cm2/plant), leaf area index (0.462) were observed in water hyacinth. The lowest height (42.20 cm), leaf number (13.70 no./plant), leaf area (45.58 cm2/plant), and leaf area index (0.12) were recorded in control. Maximum fresh and dry weights (root, stem, and leaf) were 129.19 g/plant and 57.97 g/plant found in water hyacinth, respectively. Results concluded that the overall growth and yield were achieved better in water hyacinth manure. Dhaka Univ. J. Biol. Sci. 30(1): 79-86, 2021 (January)


1989 ◽  
Vol 112 (3) ◽  
pp. 425-426 ◽  
Author(s):  
D. M. Firman ◽  
E. J. Allen

Measurements of the area of individual leaves in crops are useful in the analysis of canopy architecture as they allow determination of the structure of leaf area index in a vertical profile. This information may be of use in modelling leaf growth and the assessment of photosynthetic potential of different strata of the canopy with ontogeny (cf. Firman & Allen, 1988).


Plants ◽  
2019 ◽  
Vol 8 (8) ◽  
pp. 293 ◽  
Author(s):  
Carmine Amalfitano ◽  
Nadezhda A. Golubkina ◽  
Laura Del Vacchio ◽  
Giuseppe Russo ◽  
Mario Cannoniero ◽  
...  

Research was carried out on onion landrace (Ramata di Montoro) for seed production in southern Italy, with the aim to evaluate the effects on yield and quality of four bulb planting times in factorial combination with four densities, using a split plot design with three replicates. The number of flower stalks per plant, their height and diameter, and the inflorescence diameter decreased with the bulb planting delay and density increase. The highest plant leaf area and LAI (leaf area index), seed yield, number, and mean weight were recorded with the earliest planting time, with the lowest bulb density eliciting the highest plant leaf area but the lowest LAI and seed yield per hectare. The ratio between seeds and inflorescence weight, and seed germinability, decreased with the planting delay and density increase. Seed oil, protein, and antioxidant content (polyphenols and selenium) were highest with the last crop cycle. The polyunsaturated fatty acids, predominant in oil, increased with planting time delay, whereas the monounsaturated fatty acids decreased. Linoleic, oleic, and palmitic acid prevailed among polyunsaturated, monounsaturated, and saturated fatty acids, respectively. Planting from 20 December to 10 January with 3.3 cold-stored bulbs per m2 was the most effective combination in terms of seed yield per hectare, whereas seed oil content and quality were the best, with the last crop cycle starting on 21 February, independent of bulb density.


Genetika ◽  
2003 ◽  
Vol 35 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Nada Hladni ◽  
Dragan Skoric ◽  
Marija Kraljevic-Balalic

The main goals of sunflower breeding in Yugoslavia and abroad are increased seed yield and oil content per unit area and increased resistance to diseases, insects and stress conditions via an optimization of plant architecture. In order to determine the mode of inheritance, gene effects and correlations of total leaf number per plant, total leaf area and plant height, six genetically divergent inbred lines of sunflower were subjected to half diallel crosses. Significant differences in mean values of all the traits were found in the F1 and F2 generations. Additive gene effects were more important in the inheritance of total leaf number per plant and plant height, while in the case of total leaf area per plant the nonadditive ones were more important looking at all the combinations in the F1 and F2 generations. The average degree of dominance (Hi/D)1/2 was lower than one for total leaf number per plant and plant height, so the mode of inheritance was partial dominance, while with total leaf area the value was higher than one, indicating super dominance as the mode of inheritance. Significant positive correlation was found: between total leaf area per plant and total leaf number per plant (0.285*) and plant height (0.278*). The results of the study are of importance for further sunflower breeding work.


1998 ◽  
Vol 25 (7) ◽  
pp. 819 ◽  
Author(s):  
Michael J. Robertson ◽  
Graham D. Bonnett ◽  
R. Michael Hughes ◽  
Russell C. Muchow ◽  
James A. Campbell

Canopy development is an important determinant of crop radiation interception, and in the absence of stress is mainly driven by temperature. The responses to temperature of the component processes of canopy dynamics in sugarcane: leaf appearance, leaf size, tillering, and leaf senescence, were analysed for the commercial Australian cultivar, Q117. Data were derived under optimal growth conditions from controlled environments, and from irrigated field studies in subtropical and tropical locations. Regression of number of fully-expanded leaves in field-grown plants against cumulative thermal time revealed that the thermal time between the appearance of successive leaves increased as a function of leaf number, such that leaf 1 required 86˚Cd and leaf 40 required 160˚Cd. At any moment, on average there were 3.7 leaves still expanding on the stalks. Functions describing leaf appearance gave acceptable prediction of the time course of leaf appearance taken from independent datasets of field-grown plant and ratoon crops. Leaf size increased with leaf position, with the largest leaves observed at approximately leaf 17 and above. Combining functions describing leaf appearance and leaf size as a function of leaf position allowed estimation of leaf area index (LAI) of main stems in plant and ratoon crops in subtropical and tropical environments. Tiller LAI, derived by difference, accounted for 60–90% of total LAI at the 5- leaf stage, declining to 20–50% at the 15-leaf stage. Plant and ratoon crops were similar in terms of the amount and proportion of tiller LAI. Combining data from all field studies indicated under potential growth conditions, leaf senescence was closely related to leaf production. The functions derived in this study give a basis for simulating canopy dynamics under potential growth conditions in sugarcane, though the extent of genotypic variation for the key parameters and their modification by stress remains to be assessed.


2021 ◽  
Vol 30 (2) ◽  
pp. 159-168
Author(s):  
Shabnur Chowdhury ◽  
MK Rahman

Effects of organic manures on growth and yield of lettuce (Lactuca sativa L.) and nutrient accumulation in its leaves was examined. The experiment was conducted in a completely randomized design (CRD) replicated thrice with ten treatments involving nine organic manures and a control treatment. Growth parameters viz. plant height, leaf number, leaf length, leaf area, leaf area index and fresh and dry weight of leaf, stem and root were assessed. The highest height (23.69 cm), longest leaf (32.18cm), leaf area (5883.43cm2), leaf area index (6.434), fresh weight (85.41 g) and dry weight (42.73 g) were found in Payel organic manure. The maximum leaf number (27) was recorded in Approshika organic manure. The maximum content of nitrogen (6.12%), phosphorus (1.83%), potassium (4.11%) and Sulphur (1.69%) were observed in Payel organic manure. The best growth performance and nutrient accumulation was observed in Payel organic manure. Dhaka Univ. J. Biol. Sci. 30(2): 159-168, 2021 (July)


2018 ◽  
Vol 40 (6) ◽  
Author(s):  
Marlúcia Pereira dos Santos ◽  
Victor Martins Maia ◽  
Fernanda Soares Oliveira ◽  
Rodinei Facco Pegoraro ◽  
Silvânio Rodrigues dos Santos ◽  
...  

Abstract The estimation of pineapple total leaf area by simple, fast and non-destructive methods allow inferences related to carbon fixation estimative, biotic and abiotic damages and correlating positively with yield. The objective was to estimate D leaf area and total leaf area and of ‘Pérola’ pineapple plants from biometric measurements. For this purpose, 125 slips were selected and standardized by weight for planting in pots. Nine months after planting in a greenhouse, the plants were harvested to evaluate the total leaf area of the plant, D leaf area and D leaf length and width using a portable leaf area meter. Pearson correlation analysis was made and it was observed significative positive and strong correlation among the studied variables. Then, regression models were adjusted. It was observed that the D leaf area of ‘Pérola’ pineapple can be estimated from the length and width of this same leaf and the total leaf area can be estimated from the D leaf area.


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