This investigation was conducted at Shandweel Agricultural Research Station, Sohag Governorate, Egypt, during 2012 - 2013 and 2013 - 2014 seasons to determine phenotypic and genotypic correlation coefficients among ten agronomic characters in sugarcane (Saccharum spp.) and to analyze their interrelationships through path coefficient analysis. Thirty sugarcane clones that were selected from six bi - parental crosses (families) along with two check cultivars (GT54 - 9 and Ph8013) were laid out in a randomized complete block design with three replications at the first clonal selection stage.
The results showed that phenotypic and genotypic correlation between cane yield and its components, viz. stalk diameter, stalk weight and number stalks/fed were highly significant in the positive direction in plant cane, first ratoon and across crops. There
was also a positive and significant correlation of cane yield with Brix% and sugar yield,
however, insignificant correlation was observed with stalk height at phenotypic and
genotypic level in both plant cane and first ratoon crops.
On the other hand, sugar yield recorded a positive and highly significant phenotypic and genotypic correlation with each
of stalk diameter, stalk weight, number stalks/fed, cane yield, Brix%, sucrose percentage and
sugar recovery % , while this trait gave a negative and insignificant correlation with
stalk height in both plant cane and across crops.
The path coefficient analysis revealed that stalk weight surpassed stalk number in their phenotypic and genotypic direct effects on cane yield in plant cane, first ratoon and across crops. Stalk diameter had a large
positive direct effect on stalk weight followed by stalk length
at phenotypic and genotypic level in both crops. Brix had a negative phenotypic and genotypic direct effect on sugar
recovery, while, sucrose had a large positive phenotypic and genotypic direct effect on
sugar recovery in both plant cane and first ratoon. The path analyses further showed that cane yield and sugar recovery% were the most important components that had phenotypic and genotypic direct effects on sugar yield. Both correlation and path coefficient analyses can
provide some guide to breeders for selecting best clones and predicating selection gain.

Thirty sugarcane clones that were selected from six bi-parental
crosses (families) along with two check cultivars (GT54-9 and Ph8013)
were planted in randomized complete block design trial with three
replications and evaluated for yield and quality traits in plant cane (PC)
and first ratoon crop (FR) at the first clonal selection stage, in addition to
, estimate broad–sense heritability and genetic variance components
under Upper Egypt Conditions at Shandweel Agricultural Research
Station, Sohag Governorate, Egypt during 2013 and 2014 harvesting
seasons.
Results indicated significant differences among evaluated
clones for stalk length , stalk diameter , stalk weight , number of stalks
/fed ,cane yield , Brix%, ,sucrose %, purity%, sugar recovery% and sugar
yield in plant cane , first ratoon and across crops. Across plant cane
and first ratoon the clones, G2009 - 30 (67.17 ton/fed), G2009-
7(64.41 ton/fed), G2009-10(63.49 ton/fed) and G2009-18 (62.41
ton/fed), respectively, surpassed the two check cultivars for cane
yield, while, the highest sugar yield was recorded with clones, G2009-
10(9.02 ton/fed), G2009-27(8.25 ton/fed), G2009- 2(8.25 ton/fed),
and G2009-21(8.17 ton/fed), respectively. Genotypic variance,
heritability, phenotypic and genotypic coefficient of variation decreased
from plant cane to first ratoon for the traits , stalk diameter , ,cane yield
and Brix%, while, they increased slightly for number of stalks /fed andEgypt. J. of Appl. Sci., 29(12B): 709- 730 (2014)
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purity%. The significant genotypic effects indicated existence of genetic
variability among the genotypes and the possibility of genetic
improvement in most studied traits through selection.
Key words: Sugar cane (Saccharum spp), Plant cane, Ratoon crops, Clones,
Genetic variance, Heritability.
INTRODUCTIO

The increasing awareness of sugar production may result in growing sugarcane crop on soils where salinity may develop from the use of saline irrigation water. Hence, salt tolerance in four local sugarcane cultivars namely; PH 80-3, Giza 19-95, GT 54-9, and Giza 21-95, grown under two K-fertilization rates i.e., 48 and 96 kg K2O/fed., was determined in a 2-years pot study. Six salinity treatments were imposed on a silty clay soil by irrigation with tap water salinized with NaCl and CaCl2 (1:1 w/w). Electrical conductivity of the irrigation waters EC1 ranged from 0.54 to 6.15 dS/m. Vegetative growth and sugar yield were measured for plant and first ratoon crops.
In both seasons of study, the examined cultivars indicated significant differences in terms of tillers number, cane diameter, plant height, stalk weight, and sugar yield with increasing soil salinity, EC from 1.19 to 9.50 dS/m. The piecewise response model was used to determine the negative correlation of relative stalk and sugar yield with EC values. The relative sugar yield was unaffected by soil salinity up to an average of 1.51 dS/m. Each unit increase in soil salinity above this threshold reduced the sugar yield by 6.56 and 7.88% for plant and ratoon crops, respectively. Likewise, stalk weight response displayed the same performance, so it can be suggested that the ratoon crop is more salt sensitive than plant crop.
GT 54-9 cultivar was found to be the most salt tolerant among the studied cultivars as it produced supplementary tillers, thickest canes, tallest plants, and the highest stalk weight. As for sugar production both GT 54-9 and Giza 19-95 cultivars may be regarded as the most salt tolerant. Where GT 54-9 and Giza 19-95 produced higher plant sugar yield by 8.4% than the other two cultivars, while Giza 19-95 was superior in ratoon sugar yield by 3.50, 8.25 and 11.91% than GT 54-9, PH 80-13 and Giza 21-95, respectively. Doubling the potassium rates had insignificant effect on tillers number and cane diameter but significantly affected the plant height, stalk weight, and sugar yield. The above results indicated also that the reduction in stalk weight was attributed mainly to the reduction in plant higher rather than cane diameter and/or tillers number.
Keywords: Sugarcane, water and soil salinity, salt tolerance

Selected 227 somaclones of sugarcane var. GT54-C9 were studied in two successive seasons to investigate the potential of using tissue culture plant to propagate and to select superior clones regarding sugar yield in comparing to the control (explant donor) at the field of Sabahia Research Station. Technological characters were measured and statistical analysis were performed which involved the correlation between studied characters each other and peroxidase zymogram of selected superior clones and their explant donor was examined. The results have shown a genetic variants observed by wide range of recorded values of each measured character in both plant crop and first ratoon. Eight clones have sugar weight higher than their donor with average of 76.2 gram (which represent their superiority in the two seasons. The correlation between studied characters in both two seasons was found to be positive and significant at the first ratoon. Such clones will be used in sugarcane breeding program. Due to improved yield and the genetic changes revealed by isozyme patterns in clones tissue culture methods can be used to create superior varieties for agriculture use
Keyword: Somaclone, Plant crop, First ratoon, Isozyme