The investigation was carried out at the Regional Agricultural Research Station, Warangal, (Professor Jayashankar Telangana State Agricultural University) located at an altitude of 304 M above MSL, 17.97° N latitude and 79.60° E longitude during 2 years 2014-15 and 2015-16 utilizing both Kharif and Rabi crop seasons in each year. The main crop seasons in Telangana State can be called as rainy (June-Dec) and post rainy (Nov-April) seasons. Entire study was conducted as two experiments. The experimental material comprised of 10 parents viz., MTU 1010, WGL-32100, Ramappa, RP-Bio-5478-270, RP-Bio-5478-166, RP-Bio-5478-176, DRR Dhan-40, RP-Bio-5478-185, NH-686, NH-787, their 45 F₁ hybrids (generated from ten parents, crossed in diallel fashion without reciprocals during previous Kharif, 2014) and corresponding F₂’s (seed obtained from F₁ generation raised during successive Rabi, 2014-15) and two promising check varieties viz. BPT 5204 and Chittimuthyalu. Sufficient seed of fresh crosses was preserved and half was sown to produce F₂ seed.

During Kharif 2014, ten parents were transplanted each in four rows in a crossing block at spacing of 20 x 15 cm and 4 sets were maintained. Crosses were effected in a 10 x 10 half diallel design to produce 45 F₁ s. Selected parents were sown at staggered intervals of seven days to facilitate continuous availability of pollen during crossing. Twenty eight days old seedlings were transplanted at spacing of 30 x 15 cm. Hybridization was done by clipping method of emasculation as suggested by Jennings et al. (1981). Spikelets were emasculated in the afternoon and pollination was done in morning of next day between 11 – 1.00 P.M. Parents were crossed in a half diallel fashion without reciprocals to generate 45 F₁ s hybrids. Adequate care was taken to produce sufficient seed required for studying different generations.

After the crosses were effected during kharif, 2014, in the next rabi 2014-15 itself, all the 45 F₁s without reciprocals along with parents and two check varieties were grown for producing sufficient F₂ seed. The material (Parents, F₁s and F₂s) was planted in randomized block design replicated thrice during final season Kharif, 2015 in a separate plot for studying combining ability, heterosis and inbreeding depression. Parents, hybrids and check varieties were planted in one row of 3.0 m length adopting a spacing of 20 cm between the row and 15 cm between the plants within a row with single seedling per hill. Each entry of F₂ was planted with same spacing maintaining 120 plants for cross in each replication (8 rows).

Five parent plants and F₁s, twenty from BC₁, BC ₂ and forty from F₂ were tagged at random for each entry in each replication. The analysis for all quantitative data and quality data was done as per the standard procedures of IRRI. The mean data was used for final statistical analysis using Indostat to study the association between nutritional and cooking quality traits in rice.

In the present investigation, simple correlation studies were estimated for yield and its components for F₁ and F₂ generation, whereas, grain quality traits viz., kernel length, volume expansion ratio, kernel elongation ratio, gelatinization temperature, amylase content, protein content, iron and zinc contents in F₁ generation were recorded. The results are furnished in Table 1 & 2.

The data on days to 50 per cent flowering exhibited significant negative association in F₁ and F₂ generations with grain yield per plant as was reported by Chandrasekhar Haradari and Shailaja Hittalmani (2017). The days to 50 per cent flowering recorded a significant negative correlation with test weight (-0.3177, -0.3579), kernel L/b ratio (-0.2986, -0.6160) in F₁ and F₂ generations, respectively. Significant positive association was observed between this trait with total and productive tillers per plant in F₂ generation. (Table 1). The plant height recorded a significant negative correlation with grain yield as was earlier reported by Ratna et al. (2015). In F₁ generation, this character had non significant negative association with tillers per plant, number of grains per panicle, test weight, kernel length and kernel L/B ratio while non significant positive association with panicle length, spikelet fertility percent, kernel breadth. Plant height had negative significant association with number of grains per panicle, test weight, kernel length and kernel L/b ratio in F₂ generation.

For total number of tillers per plant, correlations were found to be non significant negative association with grain yield, number of grains per panicle, test weight, kernel length, kernel breadth, kernel L/b ratio in both generations. This trait had significant positive association with number of productive tillers per plant in F₁ and F₂ generations, respectively.

The trait, productive tillers per plant, had positive correlation with yield per plant in F₁ generation while negative correlation in F₂ generation. This trait registered non significant negative association with number of grains per panicle, spikelet fertility percent, test weight, kernel length, kernel breadth, and kernel L/B ratio in F₁ and F₂ generation while in positive association with pikelet fertility percent. Positive association between number of productive tillers per plant with grain yield per plant earlier reported by Ashok et al. (2016), Edukondalu et al. (2017), Manjunatha et al. (2017) and Srikanth Thippaniet al. (2017). Number of effective tillers plant^-1 had negative significant correlation with panicle length in F₂ as was reported by reported by Ratnaet al. (2015). The panicle length recorded significant positive association with kernel breadth (0.3630/0.3296) and positive association with grain yield, number of grains per panicle and test weight at both generations. It had negative association with spikelet fertility percent and kernel length. But, significant positive association of panicle length with grain yield plant^-1 earlier reported by Vinoth et al. (2016) and Edukondalu et al. (2017)Rukmini Devi et al. (2017). The character number of grains per panicle registered significant positive correlation with grain yield, test weight, kernel length, kernel length, kernel L/B ratio in two generations. (0.3407, 1.2713) and significant positive phenotypic association with yield (0.4703). Significant positive association of number of grains per panicle with grain yield per plant earlier reported by Vinoth et al. (2016), Ashok et al. (2016), Dhurai et al. (2016) and Chandrashekhar Haradari and Shailaja Hittalmani (2017). Spikelet fertility percent had positive correlation was observed with grain yield per plant (0.0784) in F₁ generation while negative correlation in F₂ generation. It had non significant negative correlation with kernel length, kernel L/B ratio in both generations.

Test weight had significant positive association with yield per plant (0.7708, 0.6436), kernel length (0.5440, 0.4515) and kernel l/b ratio (0.4931, 0.4271) in both generations. Significant positive correlation of test weight with grain yield per plant reported by Ashok et al. (2016) and Rukmini Devi et al. (2017). Negative correlation of this trait with number of productive tillers/plant in F₁ and F₂ generations. These results are in accordance with the results of Moosavi et al. (2015). Grain yield per plant exhibited significant correlations with number of grains per plant, test weight, kernel length and L/B ratio in both F₁ and F₂ generations respectively. Productive tillers per plant exhibited non significant positive correlation in F₁ while negative in F₂. (Table 1). Rukmini Devi et al. (2017) reported the positive association of grain yield per plant with filled grains per panicle and effective tillers.

Kernel length had significant positive association with kernel L/b ratio (0.9366, 0.8815) (Vijay Kumar, 2015) and grain yield per plant (0.6141/0.5447) (Meena et al. (2016) and Srikanth Tippani et al. (2017) in two generations and it had negative association with kernel breadth in F₂ generation.(-0.0006). Similar result was reported with grain breadth by Patel et al. (2014). Kernel breadth had a non significant positive correlation with grain yield per plant, (Madhavi Latha et al. 2005). Kernel breadth had negatively significant association with kernel L/b ratio (-0.3156, -0.4629) irrespective of generations where similar result were reported by Meena et al. (2016), Suman Rawte and Ritu R Saxena (2017). Kernel L/B ratio registered significant positive correlation with grain yield (0.4968/0.4655) in F₁ and F₂ generation as was reported by Madhavilatha et al. (2005).

The study on simple correlation suggested that selection of plants with more number of productive tillers per plant, number of grains per panicle and test weight, which had significant positive association with yield, may be taken in to account in rice breeding program for yield improvement. In addition, kernel length, L/B ratio also had significant positive correlation with grain yield per plant.

The study conclusively suggested that selection of plants with more number of productive tillers per plant, number of grains per panicle and test weight having significant positive association with yield may be used in the rice breeding programs. Kernel length, L/B ratio also had significant positive correlation with grain yield per plant, where as the zinc and iron contents were negatively correlated with cooking quality traits viz., kernel length, volume expansion ratio, kernel elongation ratio and amylase content.

Significant at 5 per cent level

Significant at 1 per cent level

Significant at 5 per cent level

Significant at 1 per cent level

References