scholarly journals GENETIC CONTROL OF VARIATION IN A SELECTED POPULATION OF RUSSIAN WILD RYEGRASS (ELYMUS JUNCEUS)

1976 ◽  
Vol 56 (2) ◽  
pp. 275-280
Author(s):  
T. LAWRENCE

Progenies from a five-genotype diallel cross in Russian wild ryegrass, Elymus junceus Fisch., were studied to assess the pattern of genetic control for F1 seed weight and a number of seedling and adult plant characters. Variation in F1 seed weight was largely determined by the maternal parent, but some control by the pollen parent was apparent. Of the seedling characters, days to emerge, rate of leaf appearance, rate of tiller appearance, and seedling dry matter yield, only days to emerge showed additive variance which is amenable to direct selection. The other three characters could be most easily exploited by a recurrent selection program. The adult plant characters, date of inflorescence appearance, P content of the forage, and organic matter digestibility indicated strong additive control which is amenable to direct selection. Dry matter yield and seed yield also showed strong additive control which was accompanied by specific combining ability and weak maternal effects suggesting good progress should be possible by direct selection methods but crossing the selections in a diallel fashion prior to formation of synthetics might be desirable. The seedling characters, rate of leaf and tiller appearance and seedling dry matter yield were interrelated and associated with adult plant yield, thus offering the possibility of screening seedlings for these characters in a recurrent selection program for improved forage or seed yield.

1979 ◽  
Vol 59 (1) ◽  
pp. 7-13 ◽  
Author(s):  
T. LAWRENCE

Progenies from a six-genotype diallel cross in Altai wild ryegrass (Elymus angustus Trin.) were studied to assess the pattern of genetic control for F1 seed weight and a number of seedling and adult plant characters. Variation in F1 seed weight was largely determined by the maternal parent, but some control by the pollen parent was apparent. Gene action was additive, but some nonadditive genetic effects were also present. All of the seedling characters, days to emerge, rate of leaf appearance, rate of tiller appearance and seedling dry matter yield showed additive control which is amenable to direct selection. Diallel analyses indicated that the adult plant characters, days to inflorescence appearance, digestible organic matter, total dry matter yield and total seed yield were controlled by strong additive control which is amenable to direct selection. The seedling characters, rate of leaf appearance, rate of tiller appearance and seedling dry matter yield were interrelated but only rate of tiller appearance was associated with adult plant yield.


1970 ◽  
Vol 12 (4) ◽  
pp. 806-815 ◽  
Author(s):  
M. D. Hayward ◽  
T. Lawrence

Progenies from a five genotype diallel cross in Lolium perenne L. were studied to assess the pattern of genetic control for seed weight, a number of seedling characters, and two adult plant characters.Variation in seed weight was largely determined by the maternal parent, but some control by the pollen parent was apparent. Gene action was additive, but some specific genetic effects were also present, suggesting possible interaction between the haploid pollen genome with a diploid ovular genome in the triploid endosperm, or alternatively between the developing seed and the female parent plant.Of the seedling characters (total germination, rate of germination, rate of leaf and tiller production, length of fifth leaf, and seedling dry matter production) only length of fifth leaf showed any additive variation which might be easily exploited.Adult plant production showed considerable variation which interacts with the season of assessment. However, the relative order of merit remained the same and only the magnitude of the differences in productivity between the families altered. This response was itself under simple genetic control.


Author(s):  
Manpreet Jaidka ◽  
J.S. Deol ◽  
Ramanjit Kaur ◽  
R. Sikka

Effect of detopping and mepiquat chloride on morphological, physiological and yield attributes of soybean cultivar ‘SL 544’ was studied. A two year investigation was conducted at Punjab Agricultural University, Ludhiana, during kharif seasons of 2014 and 2015. The experiment was laid-out in randomized complete block design (RCBD) with eight treatments viz. control, detopping (removal of 4-5 cm apical portion of main stem) at 50-55 days after sowing (DAS), mepiquat chloride @ 200 ppm (50-55 DAS), mepiquat chloride @ 200 ppm (50-55 + 65-70 DAS), mepiquat chloride 250 ppm (50-55 DAS), mepiquat chloride @ 250 ppm (50-55 + 65-70 DAS), mepiquat chloride @ 300 ppm (50-55 DAS) and mepiquat chloride @ 300 ppm (50-55 + 65-70 DAS) with four replications. Detopping had a non-significant effect on leaf area index, SPAD value, PAR interception, abscission of reproductive parts, seeds per pod, 100-seed weight, pod length and stover yield of soybean. It significantly decreased plant height, increased total dry matter accumulation/plant, number of flowers and pods/plant, pod setting percentage and seed yield over control during 2014 and 2015. At crop harvest, detopping developed optimized source-sink relationship by means of distribution of total dry matter between stem, foliage and pods by 20.4, 14.9 and 64.6 % during 2014 while 22.6, 20.1 and 57.4 % during 2015, respectively. Mepiquat chloride posed a non-significant effect on plant height, PAR interception, number of flowers/plant, number of seeds/pod, pod length and stover yield of soybean but it significantly decreased leaf area index, abscission of reproductive parts while increased the dry matter accumulation/plant, number of pods/plant, 100-seed weight and seed yield relative to control. At harvest, two foliar applications of mepiquat chloride @ 250 ppm resulted in optimized source-sink relationship by the distribution of total dry matter among stem, foliage and pods by 20.6, 10.9 and 68.5 % during 2014 while 19.5, 7.6 and 72.9 % during 2015, respectively. Occurrence of more rainfall during 2015 as compared to 2014 caused mepiquat chloride to hike seed yield as compared to detopping which is clearly witnessed by increase in pod dry weight per plant during 2015 than 2014. Conclusively, both detopping and mepiquat chloride resulted in enhancement in source-sink relationship and seed yield of soybean.


2012 ◽  
Vol 36 (2) ◽  
pp. 227-231
Author(s):  
Nargis Jahan ◽  
M M Golam Adam

A field experiment was carried out at University of Dhaka from March to July, 2011 to study the effect of time of sowing on the growth and yield of BARI mung-5. The treatments consisted of three dates of sowing viz. March 15, April 15 and May 15. The crop responded significantly to sowing time and 15 April sowing seeds produced plants having maximum plant height (68.4 cm), leaves/plant (29.33), total dry matter/plant (17.99), branches/plant (8.17), pods/plant (11.33), pod length (8.78 cm), seeds/pod (11.17), 1000 seed weight (46.52 g), seed yield/plant (5.33 g), yield/ha (1.77 t) and harvest index (29.58 %) at harvest. The seed yield decreased by 36.8 and 49.9% when seed sown early (15 March) or late (15 May) due to production of lower yield components.   DOI: http://dx.doi.org/10.3329/jbas.v36i2.12966   Journal of Bangladesh Academy of Sciences, Vol. 36, No. 2, 227-231, 2012    


Proceedings ◽  
2020 ◽  
Vol 36 (1) ◽  
pp. 201
Author(s):  
Marcal Gusmao ◽  
Delfim Da Costa ◽  
Angelo Da Costa Freitas ◽  
Kadambot H. M. Siddique ◽  
Robert Williams

Growth, development and yield of three-grain legumes (mung bean [F1], soybean [F2] and grass pea [F3]) following rice crop to enhance grain production was studied in a paddy field in the northern Timor-Leste. A split plot design was used with three water treatments (well-watered [W0], water withheld at flowering [W1] and after germination [W2]). Interaction between water treatments and species on dry matter production (p < 0.001) and seed yield (p = 0.005) was observed. In control, the highest seed yield was F1 (1.2 t/ha) followed by F2 (1.1 t/ha) and F3 (0.4 t/ha) respectively. There was a steady reduction in seed yield in F1 from W0 to W2, but almost fifty percent reduction in F2 under W1 and W2 compared to W0. F3 had little difference between water treatments. The W1 and W2 reduced number of filled pods per plant in all species compared to control (W0). Between the species, F3 had the highest filled pods per plant followed by F2 and F3. The W1 and W2 reduced seeds per pod of F1; however, it did not effect F2 and F3. There were interactions between water treatment and species on 100 seeds weight. The heaviest seeds were in F2 in the control plants, but in the F2 drought treatments (W1 and W2) seed weight were less than F3. The lowest seed weight was in F1, but there was no impact of the terminal droughts on its seed weight.


1977 ◽  
Vol 57 (4) ◽  
pp. 1085-1090 ◽  
Author(s):  
T. LAWRENCE

Selection for fast and slow germination in Altai wild ryegrass (Elymus angustus Trin.) through three cycles of selection resulted in significant differences in the speed of germination index between the two populations. The fast germinating population established significantly better in a field test than the slow germinating population. Significant differences, although not large, were also found between the populations for spring vigor, seed yield and dry matter yield. However, observations from a greenhouse test indicate that these differences were attributable to differences in stand establishment in the field test rather than directly attributable to selection for speed of germination. It is suggested that selection for fast germination would be useful in breeding better establishing strains of Altai wild ryegrass. This would have little effect on either spring vigor or yield of seed and forage.


1977 ◽  
Vol 88 (3) ◽  
pp. 605-614 ◽  
Author(s):  
P. D. Hebblethwaite

SUMMARYThe effects of irrigation and nitrogen on S. 23 perennial ryegrass grown for seed were investigated in a series of field experiments from 1972 to 1974. Irrigation significantly increased seed yield by 16% in 1972 and 52% in 1974 but had no effect in the wet year of 1973. In 1972 maximum deficit reached 110 mm at the end of July and coincided with anthesis. Consequently the yield response was due to an increase in number of seeds per unit area and no other seed yield component was affected. In 1974 peak deficit also reached about 100 mm but started to build up rapidly very early in the season and had reached 80 mm by the time that the first ears emerged. Consequently the yield response was due to increases in number of fertile tillers, number of seeds per unit area and 1000-seed weight.Irrigation had no significant effect on number of florets or seeds, except in 1974 when percentage of florets which produced seed was increased by 2%.Irrigation had some effect on threshed straw yields, total dry matter, harvest index and total number of tillers but where this occurred the response was much smaller than that of seed yield which indicates that irrigation had greater effects on the reproductive development of the crop than on yield of dry matter and tillering patterns. Increasing the quantity of nitrogen from 0 to 80 kg/ha increased seed yields, all seed yield components except 1000-seed weight, threshed straw yields and total dry matter and number of tillers at most sampling dates. Increasing the quantity of nitrogen from 80 to 160 kg/ha had little further effect on the above components except in 1972 where seed yields were significantly decreased.In 1972 number of florets was increased and percentage of florets which produced seed decreased with increasing quantities of nitrogen.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Mandakini Kabi ◽  
Bhabendra Baisakh ◽  
Manasi Dash ◽  
Swapan K Tripathy ◽  
S. Sahu ◽  
...  

The study of gene action and combining ability have been conducted in 28 F1 cross combinations along with eight parents in 8x8 half-diallel scheme following Griffing’s Approach for 14 morphoeconomic traits including seed yield and oil content in sesame. The general combining ability (GCA) and specific combining ability (SCA) component of variation were significant for parents and crosses respectively for all characters except internode length for GCA indicating role of both additive and nonadditive gene action. However, higher proportion of SCA variance (?2 sca) than GCA variance (?2 gca) revealed preponderance of non-additive gene action for all characters except capsule length and capsule width under study. Further, variance due to dominance played a significant role than additive variance in all traits except capsule width and 100-seed weight. Nirmala is considered as the best general combiner owing to its higher estimate of gca effects for yield per plant, for days to maturity, plant height, branches per plant, capsules per plant, seeds per capsule, capsule length and 100-seed weight. Among cross combinations; Rama × GT-10, AT-382 × Krishna, AT-382 × Nirmala, Krishna × Nirmala, Krishna × Uma, Nirmala × Prachi and Prachi × Uma showed significantly higher sca effect for seed yield per plant in the desired direction indicating their merit for recovery of transgressive segregants for higher productivity following reciprocal recurrent selection.


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