scholarly journals Results of fast neutron induced mutations in M1 and M2 generations of sorghum (Sorghum bicolour)

2007 ◽  
pp. 49-54
Author(s):  
Pál Pepó ◽  
Éva Erdei

Due to climatic barriers, the genetic variability of Sorghum varieties decreases away from the gene centre, therefore hybrids cultivated in Hungary are restricted to a relatively limited genetic basis. This limited genetic basis results in a lower rate of genetic improvement, so the genetic basis of cytoplasm factors are to be extended. We enhanced the diversity of primary materials by fast neutron treatment. As a result of this treatment we detected sterile, deformed specimens with double panicles in the stock treated with a dose of 12.5 Gy in the M1 generation. Agronomically usefulspecimens were found in the stock treated with 10 Gy and 7.5 Gy doses, where the leaf area index (LAI) and Harvest- index gave higher values than those of the control group. In the stock treated with 5 Gy dose, variations were less significant. In the reseeded M2 generation we detected albino specimens with extreme chlorophyll defects in the 10 Gy Zádor stock.

2013 ◽  
Vol 5 (2) ◽  
pp. 371-381 ◽  
Author(s):  
K. K. Paul ◽  
M. A. B. Miah

An investigation has been made to characterize the local accessions of Elephant foot yam collected from thirteen aroid growing districts and in-depth study on genetic variability, correlation and path coefficient for plant height, petiole length, petiole breadth, leaf area index, corm length, corm breadth, corm weight, cormel number, cormel length, cormel breadth, cormel weight and yield per plant has also been carried out. Genotypic variances and coefficient of variation for most of the characters were remarkably higher than their corresponding environmental variances, which also indicate the existence of variation in genotypic origin. High heritability with high genetic advance in percentage of mean was also observed for all characters. In the correlation study plant height, leaf area index, corm length, corm breadth, corm weight, cormel number, cormel length, cormel breath showed positive correlation with yield per plant in genotypic and phenotypic level. Leaf area index, cormel number in phenotypically and cormel number in genotypic level showed relatively high positive direct effect on yield per plant.Keywords: Amorphophallus; Genetic variability; Correlation; Path coefficient.© 2013 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved.doi: http://dx.doi.org/10.3329/jsr.v5i2.13853        J. Sci. Res. 5 (2), 371-381 (2013)


1988 ◽  
Vol 24 (4) ◽  
pp. 443-448 ◽  
Author(s):  
James H. Cock ◽  
Mabrouk A. El-Sharkawy

SummaryBreeding for high and stable yields is a major objective for cassava breeding programmes. Owing to the simultaneous formation of steins and leaves (source) and storage roots (sink), competition for assimilates implies that there is an optimum leaf area index for yield. This has led to the use of the harvest index as a practical criterion for selection. The optimal harvest index and leaf area index are discussed for selection for stressful environments. A successful strategy for developing high yielding varieties for favourable conditions is presented. Recent information has shown that selection for a slightly larger than optimal leaf area index, and hence greater biomass, can lead to stable yield in both favourable and stressful environments. Moreover, yield levels can be increased by selecting for moderate harvest indices (e.g. 0.5-0.65) and increased biomass. Longer leaf life is an integral part of this selection strategy. These concepts are discussed in detail.James H. Cock y Mabrouk A. El-Sharkawy: Caracteristicas fisiológicas para la selección de la mandioca.


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.


2016 ◽  
pp. 106-129
Author(s):  
Ariel Mactal ◽  
Justo Canare

Vulnerability of rice growing areas to strong typhoons coupled by the susceptibility of traditional rice varieties to lodging lead to low yield and poor quality of harvested rice. To address these problems, two experiments using factorial in Randomized Complete Block Design were conducted during the wet season to determine the effects of paclobutrazol and nitrogen on the lodging resistance, agro-morphological characteristics and yield performance of two traditional rice varieties Elon-elon and Palawan Red. Application of increasing concentration of paclobutrazol did not significantly affect the percentage filled spikelets per panicle, number of spikelets per panicle, weight of 1000 grains, dry matter yield, harvest index and grain yield. At all concentrations of paclobutrazol, Palawan red had the longest first and fourth internodes, more unfilled spikelets per panicle, heavier 1000 grains weight and higher leaf area index than Elonelon. On the other hand, smaller stem diameter, more productive tillers per hill and longer panicles were obtained from Elon-elon than Palawan red. Elon-elon applied with increasing rates of nitrogen in combination with 500 ppm paclobutrazol had bigger stem diameter, higher productive tillers per hill, higher number of filled spikelets per panicle, higher percentage filled spikelets per panicle, longer panicles, higher harvest index and higher grain yield than Palawan red. Apparently, Palawan red had longer first, second and third internodes, more unfilled spikelets per panicle, heavier 1000 grain weight and higher leaf area index than Elon-elon. Applications of 30 and 60 kg N per ha had significantly higher lodging index than the untreated plants. Harvest index and grain yield were lowest in plants applied with 30 and 60 kg N per ha, attributable to high lodging index. Paclobutrazol is effective in shortening the length of the lower internodes and inhibits stem elongation resulting to shorter plants with increased lodging resistance. This ultimately produced higher yield than those plants that lodged. Culm strength was reduced by high rates of nitrogen causing significant increase in lodging index. The time of lodging is crucial in predicting the yield performance of the plants. Early lodging resulted to huge reduction in yield while it has little or no effect on yield when it occurs at later stages of the rice crop.


Author(s):  
M. Ramesh Kanna ◽  
Hiramani Barman ◽  
Kasireddy Sivasankarreddy ◽  
Dikshita Gogoi ◽  
T. V. Rao ◽  
...  

The present investigation was conducted with nine genotypes in randomized block design during Rabi, 2019-20 at the instructional-cum-research farm, Assam Agricultural University, Jorhat. All the characters exhibited significant genotypic mean squares in analysis of variance except anthesis silking interval, kernel rows per ear and 100 kernel weights. High heritability coupled with high genetic advance was observed for the traits plant height, ear height, ears per plant, ear length, kernels per row, chlorophyll content, leaf area index 60 days after sowing (LAI 60 DAS), LAI 90 DAS, harvest index, grain yield per plant and grain yield per hectare. Significant genetic association of grain yield per plant and grain yield per hectare with days to 50% pollen shed, days to 50% silk, days to 100% dry husk, ear height, kernels per row, LAI 60DAS and LAI 90 DAS. Genotypic path analysis revealed that the characters, days to 50% silk, days to 100% dry husk, plant height, ears per plant, ear diameter and harvest index had the highest positive direct effects on grain yield per hectare while days to 50% pollen shed and ear height had the highest negative direct effect on grain yield per hectare. The hybrids namely, PAC 751, CP 333 and PAC 751 ELITE, were found to be the three best hybrids to possess a high estimate of desirable traits such as days to 50% pollen shed, days to 50% silk, days to 100% dry husk, plant height, ear height, ear diameter, leaf area index at 60 days after sowing, lea area index at 90 days after sowing, grain yield per plant and grain yield per hectare.


1992 ◽  
Vol 118 (1) ◽  
pp. 29-36 ◽  
Author(s):  
A. Blum ◽  
G. Golan ◽  
J. Mayer ◽  
B. Sinmena ◽  
T. Obilana

SUMMARYWhile the relative advantage of hybrids over open-pollinated varieties has long been established for temperate sorghums in developed countries, similar information for semi-tropical sorghums used in Africa and India is relatively scant, especially under conditions of drought stress. This study compared 23 hybrids with 21 open-pollinated varieties, all developed in India and/or Southern Africa. Materials were field-tested under conditions of stored soil moisture at two levels of drought stress (dryland or one supplemental irrigation) at Bet Dagan, Israel in 1989.Irrespective of the water regime, grain yield and harvest index increased and leaf area index decreased with a shorter growth duration of the genotypes. Hybrids were earlier, had a larger leaf area index, more than double the harvest index and produced more grain compared with varieties. In spite of their longer growth duration, varieties were less water-stressed than hybrids, as judged by their midday leaf water potential, relative water content and the extent of leaf rolling. The relatively poor plant water status of the hybrids could be partly ascribed to their larger leaf area index. Hybrids produced more biomass per day than varieties under low stress while varieties produced more biomass per day than hybrids under high stress. Thus, in terms of plant water status and mean daily biomass production, varieties were more drought resistant than hybrids. However, the physiological superiority of the varieties under drought stress did not result in a higher grain yield because of their inherent relatively poor harvest index, typical of the tall and late African sorghums. The superior physiological resistance to drought stress of these varieties could be translated into a yield advantage under drought stress if their potential harvest index is improved.


PLoS ONE ◽  
2021 ◽  
Vol 16 (11) ◽  
pp. e0260379
Author(s):  
Pin Zhang ◽  
Yi-kang Qi ◽  
Hong-guang Wang ◽  
Jian-ning He ◽  
Rui-qi Li ◽  
...  

Inappropriate water and fertilizer management can lead to unstable crop yields. Excessive fertilization can potentially cause soil degradation and nitrogen (N) leaching. The aim of this study was to explore the optimal N application rate on two wheat varieties with different nitrogen responding under limited water irrigation at three experimental sites in the Piedmont plain of the Taihang Mountains, China. A two-year field experiment was conducted to explore the effects of five N application rates (N0, N120, N180, N240, and N300) on winter wheat growth, leaf area index, aboveground biomass, grain yield, grain N accumulation, and net return. The results showed that N application rate significantly affected leaf area index, aboveground biomass, grain yield, and harvest index. Variety and variety × N rate interactions had a significant effect on few indicators. Compared with N0, N180 improved leaf area index, aboveground biomass, grain yield, and grain N accumulation. Compared with N240 and N300, N180 increased the harvest index and N harvest index, without significantly reducing grain yield or grain N accumulation, while enhancing a higher N use efficiency. Fertilizers applied in the ranges of 144.7–212.9 and 150.3–247.0 kg ha-1 resulted in the highest net return for the KN199 and JM585 varieties, respectively. Our study provides a sound theoretical basis for high-efficiency fertilizer utilization in sustainable winter wheat production in the Piedmont plains of the Taihang Mountains of China.


2018 ◽  
Vol 32 (2) ◽  
pp. 68
Author(s):  
Leviana Eka Vivia ◽  
Trijono Djoko Sulistyo ◽  
Mujiyo Mujiyo

<p align="left"><em>The research aims to assess the yield of baby kale that can be consumed almost all of the parts and generate organic manure free. Field research was conducted in Sindon Village, Ngemplak, Boyolali in September to October 2016. The research method uses Randomized Complete Block Design factorial with two factors, these are the dosage of manure and the age of harvest. Manure consisted of 4 doses O1 (0 ton/ha), O2 (6 tons/ha) and O3 (8 tons/ha) and O4 (10 tons/ha), and age of harvest consisted of P1 (16 DAS), P2 (20 DAS), and P3 (24 DAS). Variables observed were plant height, number of leaves, internode length, fresh weight, dry weight, leaf area index, and harvest index. The result showed that age of harvest has significant influence plant height, internode length, the number of leaves, leaf area index, fresh weight, dry weight, and harvest index. Manure doses only influence dry weight. Manure dosage of 8 ton/ha and harvest age of 16 DAS is the best combination of baby kale. Manure dosage of 10 ton/ha and harvest age of 16 DAS produce baby kale that can be consumed almost in all parts of the plant with the highest harvest index that is equal to 0.83.</em></p>


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