ABSTRACT-Cotton (Gossypium hirsutum L.) is an important fiber crop in the world being used in the textile industry and over 90% of cotton grown in the world is upland cotton. An experimental design carried out for integration of earliness genes from sindose-80 to bulgare-557 during 2005 to 2016 in the Department of Botany, University of Pune-India and Agricultural Research Center of Tehran-Iran. The first cross carried out between sindose-80 and bulgare-557 in 2005 and after crossing five years selection was done among segregated population till to F5. In 2011 the second cross carried out as a back cross between the new variety and sindose-80. Five years selection was also done after second cross. In 2016, the new earliness genotype compared with the five native and commercial cotton varieties in RCBD design. The criterion for earliness was a new earliness index of combined picking and day (CPD), which has been presented as a new earliness index in this paper along with EFD and FFT indexes. Mean comparison of traits such as three earliness indexes, boll per plant, micronaire and yield showed priority of the new earliness genotype. Comparison of the three earliness indexes indicated priority of CPD index, which is combined by both time and weight to the two conventional indexes such as EFD and FFT which are showing time and weight affects in the earliness respectively.
Key words:- Earliness, Cotton, Indexes, Gossypium hirsutum, Genotype
INTRODUCTION
Cotton is an important fiber crop in the world. Over 90% of cotton grown in the world is Gossypium hirsutum L. or upland cotton which is being used in the textile industry. Cotton also reputed as “Queen of the fiber plants”. In order to increase its yield potential and decrease the growth limitations like temperature and cloudy weather, soil moisture, soil fertility level and pest pressure, it is desirable to utilize the available genetic variability to find the earliness variety of cotton. Earliness trait in cotton is controlling by additive gene effects and this model of inheritance in cotton is useful inthe development of pure lines whereas dominance and epistatic effects can be used to exploit hybrid vigor. In upland cotton, various studies have been conducted to study the nature and magnitude of gene effects in the inheritance of different quantitative characters. [1].
Involvements of both additive and non-additive gene effects have been reported in cotton by many workers [2].
Early maturity protects cotton from frost damage, insect and disease buildups, escape pink bollworm and fertilizer and insecticide application, soil moisture depletion, less number of irrigation, decreased higher quality and leave field for the next cultivation. Earliness is shortest time to produce a profitable crop in cotton [3].
Cotton plant is in-determinant into habit and its boll maturation takes over a period of 80 days in the early flowering varieties which are associated with earliness. Plant breeders utilize percent open bolls to measure the relative maturity of cotton varieties. Environmental variations make comparisons between years difficult, on the other hands specific management decisions have deferential impacts on the diverse varieties or treatments. Morphology of a variety also can influence maturity [4]. Morphological traits that impact earliness include root/shoot ratios and leaf shape [5]. Divided leaves allow sunlight to penetrate deeper into the canopy, which improves early boll set. Varieties with lower root/shoot ratios expend less carbohydrate on soil exploration which can enhance earliness if coupled to early [6].
MATERIALS AND METHODS
An experimental project was done at the experimental field of Department of Botany, University of Pune-India and Agricultural Research Center of Tehran-Iran during 2005 to 2016. The first cross carried out between sindose-80 and bulgare-557 in 2005 and after crossing five years selection was done among segregated population till to F5. In 2011, the second carried out as a back cross between the new variety and sindose- 80. Five years selection was also done after the second cross. In 2016,the new earliness genotype compared with the five native and commercial cotton cultivars including; New earliness genotype, Sindose-80, Varamin, Oltan, Sahel and Arya, which are planted on 23 May 2016 in randomized complete block design (RCBD) with four replications. The row to row distance was maintained at 0.8m whereas plants within rows were thinned out to maintain a distance of 0.2m between plants. Each treatment plot contained four rows 12m lengths. All the agronomical, nutritional and plant protection requirements of the experiment were completed when needed.
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A procedure of the CPD earliness index which has been measured is as following:
The criteria and indexes which have been calculated for evaluation of earliness were early flowering days on the basis of days from germination to first flowering (EFD), old criterion as fraction of first picking to the total seed cotton yield (FFP) and the new combined earliness index of picking and day (CPD) which is combined by both days to picking and weight of seed cotton picking as weighted new earliness index.
Earliness Index (CPD) =
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All the fiber quality traits were studied by putting the 20-30 grams sample of lint in a latest computerized High Volume Instrument (HVI) in the fiber technology laboratory of Cotton Research Institute of Iran.
RESULTS AND DISCUSSION
Analysis of variance (ANOVA) which has been done adopting Snedecor and Cochran [7] and Steel & Torrie [8] procedures shows significant differences and genetic variation among the cultivated cultivars and varieties for studied traits such as early flowering days on the basis of days from germination to first flowering or early flowering days (EFD), fraction of first picking to the total seed cotton yield (FFP) and combined picking and day (CPD) as three indexes for earliness, staple length (mm), micronaire (gr/inch), fiber bundle strength (gr/tex), lint% (G.O.T), boll weight (gr), bolls/Plant, yield/hec (Kg), uniformity ratio (%), staple elasticity (%) and non-significant for monopodia branch (Table 1).
Table 1. Mean squares from ANOVA for various traits in cotton cultivars
| SOV | DOF | MS | F-Value | Prob | CV |
|---|---|---|---|---|---|
| Earliness (EFD) | 5 | 121.03** | 189.40 | 0.0000 | 1.71% |
| Earliness (FFT) | 5 | 474.966** | 13.81 | 0.0000 | 7.1% |
| Earliness (CPD) | 5 | 6011.79** | 111.46 | 0.0001 | 5.77% |
| Staple length (mm) | 5 | 98.651** | 66.14 | 0.0000 | 4.14% |
| Micronaire (gr/inch) | 5 | 2.713** | 33.78 | 0.0000 | 6.11% |
| Fiber bundle strength (gr/tex) | 5 | 126.185** | 73.46 | 0.0000 | 4.60% |
| Lint% (G.O.T) | 5 | 19.919** | 24.09 | 0.0000 | 2.48% |
| Boll weight (gr) | 5 | 1.492** | 11.88 | 0.0001 | 6.67% |
| Bolls/plant | 5 | 14.445** | 4.62 | 0.0094 | 16.23% |
| Yield/hec (Kg) | 5 | 1179174* | 3.30 | 0.0331 | 16.62% |
| Uniformity ratio (%) | 5 | 15.373* | 3.79 | 0.0200 | 2.42% |
| Staple elasticity (%) | 5 | 0.11* | 2.96 | 0.0460 | 2.73% |
| Monopodia branch | 5 | 0.367ns | 1.74 | 0.1869 | 34.46% |
Duncan’s mean comparison [9] shown that new earliness genotype allocated itself the first ranking of the most stu-died traits like earliness, micronaire, boll/plant and yield. Three types of indexes were used and evaluated for earli-ness in this paper. Two out of three are belong to the conventional method including early flowering days (EFD) and fraction of first picking to the total seed cotton yield (FFP) [10] and the third one is the new earliness index which is combined from picking and day (CPD) or was made by both days to picking and weight of seed cotton picking as a new weighted and combined earliness index. In the new index weight and time play the vital role and because of this mean comparison of EFD, FFT and CPD affected the ranking of studied cultivars. Table 2 shows the actual ranking of the cultivars for earliness by means of CPD method to the EFD and FFT methods. Comparison of the three earliness indexes indicated priority of CPD index which is combined by both time and weight to the two conventional indexes such as EFD and FFT that showing separated time and weight affects in earliness respectively (Table 3).
Table 2. Duncan’s mean comparison of traits in cotton cultivars
| Earliness (EFD) | Earliness (FFT)% | Earliness (CPD) | Staple length (mm) | ||||
|---|---|---|---|---|---|---|---|
| A | 53.75 | A | 94.81 | A | 182.7 | 32.63 | 4 |
| B | 45.50 | AB | 91.00 | B | 167.3 | 32.53 | 3 |
| B | 45.25 | AB | 82.94 | D | 109.3 | 31.75 | 5 |
| B | 44.50 | AB | 81.92 | D | 108.6 | 30.38 | 1 |
| C | 42.00 | B | 81.36 | D | 103.5 | 30.25 | 2 |
| C | 41.00 | C | 63.32 | E | 74.25 | 19.60 | 6 |
| Micronaire (gr/inch) | Fiber bundle strength (gr/tex) | Lint% (GOT) Boll | weight (gr) | ||||
| A | 6.175 | A | 32.45 | A | 38.36 | A | 5.960 |
| B | 4.925 | A | 32.28 | A | 38.20 | A | 5.747 |
| BC | 4.375 | AB | 31.37 | A | 37.42 | AB | 5.645 |
| C | 4.30 | B | 29.02 | A | 37.17 | AB | 5.327 |
| C | 4.10 | B | 28.52 | A | 36.61 | BC | 4.899 |
| C | 3.950 | C | 17.55 | B | 32.33 | C | 4.325 |
| Bolls/plant | Yield/hec (Kg) | Uniformity ratio (%) | Staple elasticity (%) | ||||
| A | 14.09 | A | 4305 | A | 84.93 | A | 7.25 |
| AB | 11.66 | AB | 3939 | A | 84.80 | AB | 7.10 |
| AB | 10.98 | AB | 3917 | A | 84.05 | AB | 7.10 |
| AB | 10.46 | AB | 3355 | A | 83.93 | AB | 7.07 |
| B | 9.550 | BC | 3222 | AB | 82.65 | B | 7.87 |
| B | 60/80 | C | 2853 | B | 79.70 | B | 6.80 |
Table 3 shows that the EFD index is only timely index and FFT index is only weighted index but the new index or CPD has been affected by both time and weight.
Table 3. Indexes comparison
| Index | Ranking | |||||
|---|---|---|---|---|---|---|
| EFD | 1 | 2 | 3 | 4 | 5 | 6 |
| FFT | 1 | 2 | 5 | 4 | 3 | 6 |
| CPD | 1 | 2 | 4 | 3 | 5 | 6 |
CONCLUSIONS
It is concluded that comparison of the three mentioned formulae shows the effects and playing roles of both weight and time in the CPD accurate index, despite of the only weight and time effect on FFT and EFD respec-tively. Comparison of different cotton cultivars in the inappropriate condition of cotton growth like different soil moisture, soil fertility level, pest pressure, tempera-ture and cloudy weather can affect earliness criteria which are controlling by additive quantitative genes despite of dominant qualitative genes. For this rea-son application of the accurate index like CPD for de-termination of earliness in cotton can be illustrate genet-ic effect of earliness very well and also separate the ef-fect of management and environmental effects which are playing as suppressing genetic affects.
REFERENCES
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| How to cite this article: Hosseini G: New Earliness Index and Integration of Earliness Additive Genes in the New Genotype of Cotton (Gossypium hirsutum L.). Int. J. Life. Sci. Scienti. Res., 2017; 3(3): 1016-1019. DOI:10.21276/ijlssr.2017.3.3.9 Source of Financial Support:Nil, Conflict of interest: Nil |