Possibility of Increasing Yield Potential of Rice by Reducing Panicle Height in the Canopy. I. Effects of Panicles on Light Interception and Canopy Photosynthesis.

1995 ◽  
Vol 22 (3) ◽  
pp. 441 ◽  
Author(s):  
TL Setter ◽  
EA Conocono ◽  
JA Egdane ◽  
MJ Kropff

A new rice (Oryza sativa L.) plant type is proposed which is aimed at greater light interception by the leaves during grain filling and reduced susceptibility to lodging. This plant type is based on lowering panicle height in the canopy so that leaves are able to intercept more radiation. Panicle height of four cultivars with high yield potential ranged from 80 to 95% of canopy height at 14 days after flowering (DAF). Harvested panicle area index of two of these which were two tropical cultivars amounted to 0.45-0.57 m2 m-2, while the leaves above the panicles intercepted only 4-12% incident radiation at midday in these cultivars at 14 DAF. The potential impact of lowering panicle height in the canopy on canopy photosynthesis was evaluated by panicle removal. When panicles were removed, the irradiance at the bottom of the panicle layer of the canopy increased from 52 to 80%. At 11 DAF, net canopy photosynthesis of two cultivars similarly increased by 42-52% following removal of panicles. Increases in canopy photosynthesis were mainly due to increased light interception by leaves within the canopy since there were little or no changes in canopy dark respiration or in net leaf photosynthesis rates at the same irradiance following panicle removal. Optimum panicle height in the canopy and the effect of different panicle area index is further examined using a physiological model for light competition, INTERCOM. Reduced panicle height in the canopy is discussed in terms of considerations for and impacts of lowering panicle height in the canopy on canopy photosynthesis and yield of rice.

1996 ◽  
Vol 23 (2) ◽  
pp. 161 ◽  
Author(s):  
TL Setter ◽  
EA Conocono ◽  
JA Egdane

Reduced panicle height in a rice crop canopy may have beneficial effects of increasing yield potential through reduced shading of leaves leading to greater canopy photosynthesis. Effects of different panicle height in the canopy were evaluated in glasshouse and field experiments using isogenic lines with elongated upper internodes (EUI lines) from two cultivars. Isogenic lines of IR36 and IR50 with elongated upper internodes (IR36EUI and IR50EUI) had panicle heights at the top of the canopy of 96-100% of canopy height, while lines with low panicle heights had panicles which were 74 and 82% of canopy height respectively. Lines with low panicle height had about 10% more of the total leaf area index (LAI) above panicles and this resulted in up to 35% greater light interception by leaves above panicles relative to high panicle height plants. At 5 days before flowering IR36 and IR36EUI had equal canopy photosynthesis, while at flowering, lines had equal shoot nitrogen percentage and LAI. At maturity spikelets per mainstem were not significantly different. At 0, 7, 14 and 21 days after flowering (DAF), IR36, with low panicle height, had 10-30% greater canopy photosynthesis than IR36EUI; greater canopy photosynthesis was observed for IR50 relative to IR50EUI. These beneficial effects of low panicle height on canopy photosynthesis occurred even though the maximum single leaf photosynthesis and respiration rates were similar in both isogenic lines during grain filling. In the field and in a glasshouse experiment where plants were arranged into canopies, IR36, with low panicle heights had 15-40% greater yields than the isogenic line IR36EUI with high panicle heights; greater yields also occurred for IR50 than IR50EUI.


2020 ◽  
Vol 8 (1) ◽  
pp. 387
Author(s):  
Denise Maria Grzegozewski ◽  
Elizabeth Giron Cima ◽  
Miguel Angel Uribe-Opazo ◽  
Luciana Pagliosa Carvalho Guedes ◽  
Jerry Adriani Johann

In this work, the aim was to evaluate the existence of spatial association of the municipal average official soybean yield (t ha-1) with agrometeorological data and vegetation indices. The information was observed by ten-day periods, in crop years 2010/2011, 2011/2012 and 2012/2013 in the State of Paraná. Local univariate spatial correlation (LISA index), as well as global bivariate correlation (L statistics) were calculated. With this study, we identified neighboring municipalities with high yield in the West as well as municipalities that are located with low-low yield Northwestern, showing positive spatial autocorrelation (IMG=1), significative (p-value < 0.05). In addition, there were differences between seeding times in different regions, and climate irregularity during flowering periods and grain filling in crop year 2011/2012 throughout the state, which caused a large drop in production in all municipalities of the state of Paraná. The analysis of local spatial association showed that in the three crop years, the Northwest region presented a significant low yield potential of soybean (p-value < 0.05). In addition, it was observed that the period from the 3rd ten-day period of October to the 2nd ten-day period of January was essential for the soybean cycle in the different regions of the state, since this period encompasses the critical phases of crop. Differences were also observed between the crop years studied, regarding the agrometeorological variables, which affected soybean yield mainly in the Western region of Paraná – Brazil.


Author(s):  
Avinash Kumar ◽  
Ashutosh Kumar ◽  
N. K. Singh ◽  
Rajesh Kumar ◽  
S. K. Singh ◽  
...  

In the present investigation, 10 parents and their 45 crosses (half diallel) along with 2 standard checks (Rajendra Nilam and Rajendra Mahsuri-1) were evaluated during Kharif, 2018 in Randomized Complete Block Design (RCBD) with 3 replications at Rice Farm Section, Dr. Rajendra Prasad Central Agricultural University (RPCAU), Pusa, Bihar. The objective of this study was to identify promising rice genotypes having desirable combination of morphological traits along with high grain iron and zinc content and high grain yield potential. The results of variability parameters indicated that ample amount of genetic variability was present for all the studied traits. Most of the traits showed high heritability coupled with high genetic advance indicating fruitfulness of selection for improvement of these traits. One genotype (P2×P7) with high grain iron (16.10 ppm) and grain zinc (26.40 ppm) content along with high yield (43.12 g/plant) was identified. Genotypes with high grain iron coupled with high grain yield (P7×P9, P8×P9, P5×P7 and P5×P9) and high  grain zinc content coupled with high grain yield (P4×P7, P9×P10, P8×P9 and P5×P7) were also identified. These promising genotypes identified can be used further in breeding programmes to obtain superior segregants with high grain micronutrient content and high grain yield.


Agronomy ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 2346
Author(s):  
Qingru Wang ◽  
Huanxuan Chen ◽  
Yingchun Han ◽  
Fangfang Xing ◽  
Zhanbiao Wang ◽  
...  

The photosynthetically active radiation (PAR) of crop canopy is highly related to yield formation, but how it relates to yield and yield distribution is not well understood. The focus of this study was to explore the relationship between light competition under different densities and yield distributions of cotton. The experiment was conducted in 2019 and 2020 at the Cotton Research Institute of the Chinese Academy of Agricultural Sciences in Anyang city, Henan Province, China. A randomized block design was employed, with a total of three repeats. Each repeat had six density treatments: D1: 15,000; D2: 33,000; D3: 51,000; D4: 69,000; D5: 87,000; and D6: 105,000 plants·ha−1. As predicted, the results showed that the canopy light interception, leaf area index, plant height, and biomass of high-density cotton were higher than those of low-density cotton. The aboveground biomass produced by D6 was the highest, and was 12.9, 19.5, 25.4, 46.3, and 69.2% higher in 2019 and 14.3, 19.9, 32.5, 53.7, and 109.9% higher in 2020 than D5, D4, D3, D2, and D1, respectively. Leaf area, plant height, biomass, boll number, and boll weight were significantly correlated with the light interception rate. D5 (87,000 plants·ha−1) had a higher light interception rate and the highest yield. The highest lint yields produced by D5 were 1673.5 and 1375.4 kg·ha−1 in two years, and was 3.2, 4.3, 5.6, 9.7, and 24.7% higher in 2019, and 6.8, 10.6, 13.5, 21.5, and 34.4% higher in 2020 than D6, D4, D3, D2, and D1, respectively. The boll retention of the lower fruit branch under D5 reached 0.51 and 0.57 in two years, respectively. The shedding rate of the upper fruit branch decreased with the increase in cotton density in two years. The boll retention rate and shedding rate in the lower part of cotton plants were most closely related to light interception, with R2 values of 0.91 and 0.96, respectively. Our study shows cotton yield could be improved through higher light interception by optimizing planting density and canopy structure.


1997 ◽  
Vol 48 (2) ◽  
pp. 231 ◽  
Author(s):  
M. P. Bange ◽  
G. L. Hammer ◽  
K. G. Rickert

A simple framework was used to analyse the determinants of potential yield of sunflower (Helianthus annuus L.) in a subtropical environment. The aim was to investigate the stability of the determinants crop duration, canopy light interception, radiation use efficiency (RUE), and harvest index (HI) at 2 sowing times and with 3 genotypes differing in crop maturity and stature. Crop growth, phenology, light interception, yield, prevailing temperature, and radiation were recorded and measured throughout the crop cycle. Significant differences in grain yield were found between the 2 sowings, but not among genotypes within each sowing. Mean yields (0% moisture) were 6·02 and 2·17 t/ha for the first sowing, on 13 September (S1), and the second sowing, on 5 March (S2), respectively. Exceptionally high yields in S1 were due to high biomass assimilation associated with the high radiation environment, high light interception owing to a greater leaf area index, and high RUE (1·47–1·62 g/MJ) across genotypes. It is proposed that the high RUE was caused by high levels of available nitrogen maintained during crop growth by frequent applications of fertiliser and sewage effluent as irrigation. In addition to differences in the radiation environment, the assimilate partitioned to grain was reduced in S2 associated with a reduction in the duration of grain-filling. Harvest index was 0·40 in S1 and 0·25 in S2. It is hypothesised that low minimum temperatures experienced in S2 reduced assimilate production and partitioning, causing premature maturation.


2018 ◽  
Vol 44 (4) ◽  
pp. 507-514
Author(s):  
MU Kulsum ◽  
MJ Hasan ◽  
MN Haque ◽  
M Shalim Uddin ◽  
KM Iftekharduddaula

Genotype by environment interaction (GEI) is a major complication in plant breeding. Authors used additive main effects and multiplicative interaction (AMMI) to evaluate the effects of GEI in hybrid rice genotype and their adaptation in three years at four locations. Among rice hybrid genotypes ACI93024 was stable in all environments with high yield potential. Using AMMI analysis AMMI 1 biplot showed the genotypes HS-273, Heera-2, ACI-2 and HRM-02 were highly stable with moderate yield potential but the genotype ACI93024 was more adapted to a wide range of environment than the rest of the genotypes, while BRRI dhan28 indices the lowest stability. ACI-2, LP-70 and Mayna were specifically adapted to the environment of Rangpur, Jessore and Gazipur, respectively. Comilla was identified as stable environment for all the genotypes.


1991 ◽  
Vol 116 (1) ◽  
pp. 23-36 ◽  
Author(s):  
E. Acevedo ◽  
P. Q. Craufurd ◽  
R. B. Austin ◽  
P. Pérez-Marco

SUMMARYResults are reported from nine field trials carried out in 1985/86 and 1986/87 aimed at identifying plant traits which are associated with high yield in barley in low-rainfall Mediterranean areas. Thirtyseven two-rowed and 35 six-rowed genotypes, representing the known diversity in traits considered to be useful, were compared in trials at three sites differing in expected annual rainfall (212–328 mm) in northern Syria, and in droughted and irrigated trials at Cambridge, UK. Yield, its components and other morphological and developmental traits were measured and correlations calculated.Grain yields of the two- and six-rowed groups of genotypes were similar at all sites except in the irrigated trial in Cambridge, where the six-rowed genotypes gave the highest yield. Aside from the known difference in number of ears and number of grains/ear between two- and six-rowed genotypes, the simple correlations between grain yield and measured traits suggested that important traits for high yield in two- and six-rowed genotypes in dry environments were prostrate habit, vigorous seedling growth, good ground cover, early ear emergence, many ears/m2 and large grains. In the two-rowed genotypes, short stature and a short grain-filling period were also important, while in the six-rowed genotypes, tall stature, high straw yield, many grains/ear and long peduncles were important. Correlations of these characters with an index of drought susceptibility and with yield adjusted for yield potential and date of ear emergence supported the conclusions based on the simple correlations.The physiological basis of the correlated traits is discussed and the implications for breeding are considered.


1999 ◽  
Vol 79 (1) ◽  
pp. 107-108 ◽  
Author(s):  
S. J. Park ◽  
F. Kiehn ◽  
T. Rupert

AC Ole is a high-yielding pinto bean (Phaseolus vulgaris L.) cultivar with mid-season maturity. It has high yield potential and an upright plant type, suitable for direct combine harvest. AC Ole seed has acceptable cooking/canning quality. It is resistant to races 1 and 15 of bean common mosaic virus. Key words: Phaseolus vulgaris, dry bean, cultivar description


1980 ◽  
Vol 31 (4) ◽  
pp. 673 ◽  
Author(s):  
MM Ludlow ◽  
DA Charles-Edwards

Dry weight, leaf area, light interception and canopy photosynthesis were measured during 3- or 5-week regrowth periods of Setaria anceps/Desmodium intortum swards cut to 7.5 or 15 cm. Dry matter production during the experiment and over the growing season increased with cutting height and with interval between defoliations, but the proportion of grass to legume was unaffected. These effects of defoliation on dry matter production were similar to those estimated for integrated canopy photosynthesis from measured light interception and calculated leaf photosynthetic characteristics. Height and frequency of defoliation had no effect on canopy extinction coefficient for light, nor on the leaf photosynthetic characteristics, except for the first 1-2 weeks after defoliation when leaf photosynthetic rates appeared to be depressed. The main effects of height and frequency of defoliation on dry matter production were through their effects on leaf area index and light interception.


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