scholarly journals Radiation interception, light extinction coefficient and leaf area index of wheat (Triticum aestivum L.) crop as influenced by row orientation and row spacing

2006 ◽  
Vol 2 (2) ◽  
pp. 43 ◽  
Author(s):  
M. M. Lunagaria ◽  
A. M. Shekh
Sensors ◽  
2015 ◽  
Vol 15 (2) ◽  
pp. 2860-2872 ◽  
Author(s):  
Carlos Poblete-Echeverría ◽  
Sigfredo Fuentes ◽  
Samuel Ortega-Farias ◽  
Jaime Gonzalez-Talice ◽  
Jose Yuri

Author(s):  
Ranjana Jaiswal ◽  
S. C. Gaur ◽  
Sunil K. Jaiswal ◽  
Anil Kumar

Problem: Wheat (Triticum aestivum L.) is one of the principal cereal crops grown worldwide and one of the important staples of nearly 2.5 billion of world population. India ranks second position in terms of both in area and production after china. The substantial improvement in production is utmost necessary to feed the growing population. Objective: In India, wheat requirement by 2030 has been estimated at 100 million metric tons and to achieve this target, wheat production can be increased either through horizontal approach i.e. by the increasing area under cultivation or through vertical approach i.e. varietal/ hybrid improvement. For effective selection and utilization of superior genotype in the germplasm lines, knowledge of genetic parameters such as genetic variability, heritability and genetic advance is essential. Materials and Methods: The experimental material comprised of ten parents, their 45 F1s and 45 F2s developed by the crossing of 10 parents viz. HUW 510, HUW 234, HUW 468, UP 2338, HD 2402, RAJ 1972, HD 2329, LOK-1, SONALIKA and K 65 in half-diallel programme to study the fourteen characters. The final trial of F1, F2 including parents was conducted during Rabi 2014-15 with three replications employing Randomized Complete Block Design at Research Farm, BRDPG College, Deoria, Uttar Pradesh, India. Result: Wider range of phenotypic coefficient of variation (PCV) was observed for all the traits in F1 generation ranged from 2.19 (days to 50% flowering) to 13.47 (leaf area index) while, genotypic coefficient of variation (GCV) ranged from 1.50 (days to 50% flowering) to 11.28 (leaf area index). High heritability was observed in both F1 and F2 generation for leaf area index and day to maturity while, moderate to low level of heritability was recorded for other characters. The high value of genetic advance was not recorded in both F1 and F2 generation. Only moderate to the low value of genetic advance was observed for all the fourteen characters under study. Conclusion: Estimate of phenotypic and genotypic coefficient of variation of fourteen characters in both generations reveals sufficient variability indicating ample scope for genetic improvement of these traits through selection. Moderate level of heritability accompanied with a moderate level of genetic advance was observed for plant height, leaf area index, days to maturity and grain yield per plant in both F1 and F2 generation indicates additive gene effect and selection may be effective.


1984 ◽  
Vol 11 (4) ◽  
pp. 255 ◽  
Author(s):  
HM Rawson ◽  
RL Dunstone ◽  
MJ Long ◽  
JE Begg

Well watered mini-crops of sunflower were grown either in summer or winter in glasshouses maintained under five temperature regimes and a 16 h photoperiod. A field crop was grown concurrently with the summer glasshouse study. Summer radiation (25.5 MJ day-1) increased the size and/or number of many of the variables measured compared with winter radiation (9.5 MJ day-1). However, there was interaction between light and temperature upon phenological development, plant height, leaf number and harvest index. Seed production declined at temperatures above 18/13°C in summer and above 24/19°C in winter radiation, but fatty acid composition of the seed oil changed progressively with increasing temperature and was unaffected by radiation. Leaf area per plant increased faster under summer than winter radiation and in almost all temperature regimes reached considerably higher final values which resulted in a greater percentage of the incident radiation being intercepted. Temperature, though affecting the growth patterns and final areas of individual leaves in the canopies, did not alter the relationship between leaf area index and radiation interception. The light extinction coefficient changed with leaf area index and differed between summer and winter. Biomass per plant at maturity (B, g) was best related to radiation interception up to anthesis (I, MJ m-2), such that B = -234 + 541ogl, r2 = 0.91, but seed number (S) was correlated similarly with radiation interception and with the number of degree days (D) accumulated between floral initiation and anthesis (S = 1137+ 0.0051-0.762D, R2 = 0.90). Yield (Y, g per plant) was dependent on seed number, mean temperature (T) and radiation intercepted between anthesis and maturity, and the leaf area present at anthesis. However, over 97% of the variation in yield could be accounted for by the temperature and radiation factors in the manner Y = 39.07+0.047I- 1.26T. Harvest index and yield were not correlated for the cultivar examined.


Agriculture ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 834
Author(s):  
Tianyao Meng ◽  
Jialin Ge ◽  
Xubin Zhang ◽  
Xi Chen ◽  
Guisheng Zhou ◽  
...  

Grain yield was greatly increased during the genetic improvement of japonica inbred rice since the 1980s in Jiangsu, east China; thus, an improved plant morphology should be expected, considering that plant morphology is a decisive factor determining grain yield. Twelve representative japonica inbred rice released from 1983 to 2013 were grown in the same fields in 2019 and 2020. Grain yield increased (p < 0.01) at 63.3 kg ha−1 year−1 across 2 years among rice cultivars released in different periods. The genetic improvement in grain yield was associated with increased spikelets per panicle. Single panicle weight, number of primary and secondary branches, and number of grains on primary and secondary branches were all increased with a year of release. Generally, the width of top three leaves positively correlated (while angle of top three leaves and light extinction coefficient negatively) correlated (p < 0.01) with year of release. Leaf area per tiller and leaf area index at heading and maturity, specific leaf weight, leaf photosynthetic rate, and SPAD values after heading were all increased linearly with year of release. Plant height exhibited a positive (p < 0.01) trend with year of release, as well as stem weight per tiller and K and Si concentrations of stem. Spikelets per panicle, width of top three leaves, plant height, and leaf area index, and specific leaf weight after heading positively correlated (while angle of top three leaves and light extinction coefficient negatively) correlated (p < 0.01) with grain yield and single panicle weight. Our results suggested that modern japonica inbred rice exhibited expanded sink size by spikelets per panicle, higher leaf area through leaf width, optimized leaf photosynthetic capacity, lower leaf angle and light extinction coefficient, and enhanced stem strength. These improved plant morphologies facilitated yield increases of japonica inbred rice since the 1980s in east China.


2020 ◽  
Vol 42 ◽  
pp. e18
Author(s):  
Levi Pires de Andrade ◽  
Jonathan Willian Zangeski Novais ◽  
Marta Cristina de Jesus Albuquerque Nogueira ◽  
Luciana Sanches ◽  
José De Souza Nogueira ◽  
...  

The knowledge of the radiative characteristics of an area is essential to understanding the flows of matter and energy. The value of the Light Extinction Coefficient (K) is a parameter that describes the efficiency of the interception of light in a given canopy, being required, as input, for several SWAP (Soil-Water-Atmosphere-Plant) models, which allow the characterization of the interactive properties among  soil, plant and atmosphere concerning these exchanges of matter and energy. This study aimed to obtain the light extinction coefficient (K) for a savanna fragment located in the urban area of Cuiabá. The used data correspond to one measurement each month, totaling twelve measurements in 30 points during the period from October 2014 to September 2015. The measured variables  were the LAI (Leaf Area Index), the photosynthetically active incident radiation (PARinc) and the transmitted radiation  (PARtrans), and the calculated ones were the zenith angle (Zh) and the extinction coefficient (K). Was observed an annual variability for the light extinction coefficient between 0.49 and 0.69. There are seasonal changes that interfere with the canopy geometry and the position of the study area in relation to the solar radiation incidence, concluding that the K variability is predominantly temporal.


2011 ◽  
Vol 103 (1) ◽  
pp. 119-122 ◽  
Author(s):  
Jim Kiniry ◽  
Mari-Vaughn Johnson ◽  
Robert Mitchell ◽  
Ken Vogel ◽  
Jerry Kaiser ◽  
...  

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