Dr Vinay Mahajan, Email: email@example.com
Seventy-two diverse genotypes of spring wheat were treated with a chemical hybridizing agent CH9832 to study its effects on important morphological and physiological characters. Spikelets/spike was significantly and positively correlated with plant height and spike length. Treatment of CH9832 causes significant change in association between all characters except between plant height and spikelets/spike. In addition, CH9832 cause significant earliness in genotypes as well as reduction in plant height. Therefore, days to heading and plant height are important characters for better seed setting during hybrid seed production in wheat.
Key Words: Chemical hybridizing agent, correlation and wheat
Wheat (Triticum aestivum) is the second most important crop after rice in India. Novel methods of breeding like exploitation of heterosis through hybrid wheat may become an important factor to achieve the targets of 109 mt by 2020AD from the present levels of 74.25 mt of wheat production. The technology to produce hybrid wheat through chemical hybridizing agent (CHA) depends upon the understanding of the effect of CHA on morphology and physiological characters. The objective of the present investigation is to study the association among CHA treated and normal untreated diverse genotypes of wheat.
The study material consisted of 72 diverse genotypes of wheat collected
from national and international wheat programmes. Two plots of each genotype
were planted on 23rd November 1999 at Directorate of Wheat Research,
Karnal, in two rows of two meters length and the distance between rows was 23cm.
One plot of each genotype was sprayed with a chemical hybridizing agent CH9832
at a dose of 1000 ppm along with 2ml of TWEEN 80 at a growth stage when spike
length was 7-10mm (Mahajan and Nagarajan 1998; Mahajan et al 2000).
Observations were recorded for days to 75% heading on plot basis and flag leaf area, plant height, spike length and spikelets/spike on five plant basis. The flag leaf area was the product of flag leaf length, flag leaf breadth and 0.80. The per cent change was calculated in treated over the normal untreated plots. Correlation coefficient (r) was calculated among various characters following Sendecor & Cochran (1967). The Z-test was used to test difference between the correlation coefficients obtained in CHA treated and normal untreated plots (Sendecor & Cochran, 1967).
In the present investigation, correlation studies among various
characters in CHA treated and normal untreated crop indicated that spikelets/spike
was significantly and positively associated with plant height and spike length (Table
1). In CHA treated genotypes, a significant positive association between
plant height and spike length as well as between days to heading and spikelets/spike
was observed. On the other hand, flag leaf area showed a significant positive
relationship with spike length and spikelets/spike in normal untreated
genotypes. Song et al (1997) reported
that plant height had strong significant positive correlation with grain weight
and spikes/plant as well as between spike length and grains/spike. Also, a
strong negative association was between plant height and grains/spike; spike
length and spikes/plant; grains/spike and spikes/plant; and 1000-grain weight
and spikes/plant. A significant positive correlation between heading date and
grain yield was observed by Taya (1993).
The difference between correlation co-efficient of CHA treated and normal
untreated genotypes were tested using Z-test (Table
1). On treatment with CH9832, there was a significant change in correlation
values among all the characters except between plant height and spikelets/spike.
The percentage change of different characters under study in CHA treated over normal untreated along with correlation studies between them help in identifying characters, which are significantly affected by CH9832 treatment. The present investigation indicated that there was significant earliness on CH9832 treatment along with significant reduction in plant height (Table 2). Although there was a numerical change on treatment in flag leaf area, spike length and spikelets/spike but the correlation coefficients were not significant. Hence days to heading and plant height are important character which become important for better nicking between male and female parents leading to better seed setting during hybrid wheat seed production.
The Authors are grateful to Indian Council of Agricultural Research, for providing financial assistance through A P CESS fund project on "Development of Hybrid Wheat". We are also grateful to PI (Crop Improvement) for providing necessary facilities for the experimentation.
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