Linseed or Flax (Linum usitatissimum L.) is a conventional oilseed as well as a fiber crop and belongs to Linaceae family with chromosome number 30. Linseed oil is colorless to yellowish and obtained from the dried ripe seeds of linseed. It is native to the region extending from the eastern Mediterranean to sub-continent and was probably first domesticated in the Fertile Crescent. Linseed was extensively cultivated in ancient Ethiopia and ancient Egypt. A discovery reported in 2009 of spun, dyed, and knotted wild linseed fibers in a prehistoric cave in the Republic of Georgia shows that the plant was already in use by humans at the surprisingly early date of 30,000 B.C [1] . Flax is an erect annual plant growing to 1.2 m (3 ft 11 in) tall, with slender stems. The leaves are glaucous green, slender lanceolate, 20 - 40 mm long and 3 mm broad. The flowers are pure pale blue, 15 - 25 mm diameter, with five petals; they can also be bright red. The fruit is a round, dry capsule 5 - 9 mm diameter, containing several glossy brown seeds shaped like an apple pip, 4 - 7 mm long [2] . Its fiber is used in the manufacturing of canvas, cloth, water resistant pipes, paper and strawboard. Linseed oil is used in the manufacturing of paints and varnish, oil cloth and linoleum [3] .

In Pakistan, seed flaxes are cultivated for seed purposes from which oil is extracted. The material remaining after extraction of fibre can be pulped for use in the manufacture of paper and straw board. Linseed oil is used in paints, varnishes and cloth and linoleum. Its by-product oil cake or meal is used as cattle feed and as manure for giving prolonged fertility to soil. Linseed contains 32% - 34% oil in seed and good quality fibre extracted from the straw. Linseed has got a great economic value for the commercial utility of its oil and fibres. Linseed has numerous medicinal uses. Its oil is used in local medicines as demulcent, emollient and laxative and is taken orally in bronchial infection and diarrheal. It is also used commercially in soap factories [4] .

Genetic diversity is the pre-requisite for genetic improvement of any crop. The progress in developing a superior variety depends largely on the genetic basis of selection of diverse parents and the breeding approach. The progress in breeding for such characters is determined by the magnitude and nature of interactions between their genotypic and phenotypic variability under varying conditions of soil and climate. Hence partitioning the overall variability into its heritable and non-heritable components with the help of genetic parameters such as genetic co-efficient of variation, heritability and genetic advance constitutes an important step in plant breeding programme. For a rational approach towards the improvement of seed yield, selection has to be made for the components of yield. However, the heritable variation is often masked by non-heritable variation, which creates difficulty in selection programme. This suggests the need for partitioning the overall variability into heritable and non-heritable components, which enables the breeder to evolve suitable breeding procedures. The present study was carried out on the screening selected linseed genotype for yield performance.

The present study was conducted during the year 2013-14 on the screening of the selected linseed genotypes for yield performance. The experiment was laid out at the experimental fields of Oilseeds Section, Agriculture Research Institute, Tando Jam in a three replicated Randomized Complete Block design. The experimental material comprised of 11 new linseed genotypes and a commercial check. The seeds were sown by drill method, keeping plant to plant and row to row spacing of 20 and 30 cm, respectively. The observations were recorded by labelling normal looking five plants at random in each replication for all the genotypes evaluated.

Varieties:

The experimental crop was well grown and thinned to maintain the recommended spacing between plants. The chemical fertilizers and irrigations were applied as per recommended doses of oilseeds. All the recommended cultural practices were carried out at appropriate time. The data were recorded as per the following procedures.

The present study was carried out during the year 2013-14 on the screening of the selected linseed genotypes for yield performance and associations were calculated amongst yield and its contributing traits. The experimental material comprised of eleven new linseed genotypes and a commercial check (Ilsi). The linseed genotypes included: L-53, C-W-2, Shikarpur 2, P⁻¹6-4, L-8, 11⁻¹06, Hala 3, L⁻¹7, Santane, Summit, L⁻¹0 and Ilsi 90 (Check).

The mean squares drawn from the analysis of variance for the traits days to 75% flowering, days to 90% maturity, plant height, primary branches plant⁻¹ and seeds capsule⁻¹ are shown in Table 1, while the mean squares for the traits capsules plant⁻¹, 1000 seed weight, seed yield plant⁻¹, seed yield plot⁻¹ are given in Table 2.

The performance of wheat genotypes with regards to days to 75% flowering, days to 90% maturity, plant height (cm), primary branches plant⁻¹ and seeds capsule⁻¹ is given in Table 3; while the data for traits like capsules plant⁻¹, 1000 Seed weight (g), seed yield plant⁻¹ (g), seed yield plot⁻¹ (g) are presented in Table 4. The correlation coefficients (r) amongst the traits studied for various traits are presented in Table 5, respectively.

^**Significant at 1% probability level.

^**Significant at 1% probability level.

Means followed by similar alphabetic letters are not significantly different from each other according to DMR test.

Means followed by similar alphabetic letters are not significantly different from each other according to DMR test.

The mean squares with regards to linseed yield and its contributing traits of various genotypes (Table 1 and Table 2) showed that all the genotypes differed significantly (P < 0.05) from each other for their growth and yield traits such as: days to 75% flowering, days to 90% maturity, plant height, primary branches plant⁻¹, seeds capsule⁻¹, capsules plant⁻¹, 1000 seed weight, seed yield plant⁻¹ and seed yield plot⁻¹. This significance in variation in the growth and yield traits of different wheat genotypes might be associated with genetic makeup of their parental materials.

Development of crop yield through improvement in individual plant traits are of considerable importance. In Pakistan, seed flaxes are cultivated for seed purposes from which oil extracted. Linseed oil is used in paints, varnishes and cloth and linoleum. The material remaining after extraction of fiber can be pulped for use in the manufacture of paper and straw board. Linseed has got a great economic value for the commercial utility of its oil and fibers. Its oil is used in local medicines as demulcent, emollient and laxative and is taken orally in bronchial infection and diarrhea. It is also used commercially in soap factories; In Pakistan among those, availability of new varieties is most important issue [4] [8] , to improve crop yield, development of new varieties with high yields and more responsive to input application are needed [9] , number of capsules per plant, number of seeds per capsule, 1000-seed weight and seed yield of flax cultivars differ significantly among varieties and apart from varieties these traits were improved with increasing input levels [10] .

The analysis of variance suggested significant (P < 0.05) variation among linseed genotypes for all the traits studied in this experiment. Most of the genotypes attained flowering and maturity earlier than the check variety; while P⁻¹6-4 surpassed Ilsi-90 for primary branches; and most of the remaining genotypes were at par with the commercial check for primary branches. Genotype L⁻¹0 surpassed the commercial check for capsules plant⁻¹ and L-8 was at par with the commercial check; while none of the genotypes could surpass commercial check variety for seed index, but 11⁻¹06, Hala-3 and Summit also showed promising performance regarding the seed index. All the genotypes tested in this experiment such as L-53, C-W-2, Shikarpur 2, P⁻¹6-4, L-8, 11⁻¹06, Hala 3, L⁻¹7, Santane, Summit, L⁻¹0 surpassed the commercial check variety Ilsi-90 for seed yield plot⁻¹.

Linseed genotypes developed through various breeding programs varied significantly (P < 0.05) for their agronomic performance & improved with the development of new strains [8] - [11] , Varieties are differ from each other in genetic make up for growth and yield, plants height and branches, capsules plant⁻¹, seed, straw yields and oil yield differ significantly among genotypes [12] [13] , revealed the biomass and net primary productivity were comparatively higher in cv. LC-54 than NP-5. Some other researchers revealed in their studies, it also varied from days to flowering, seed yield, plant height and branches plant⁻¹ and also significant variation in genotypes and their characteristics [14] - [17] revealed that seed yields were highest in linseed cv. Jawahar-23 (1.61 t ha⁻¹) followed by RLC⁻¹ (1.51 t ha⁻¹), RLC-2 (1.42 t ha⁻¹) and T-397 (1.28 t ha⁻¹).

The present study further showed that the correlation coefficient for yield and its contributing traits of linseed genotypes was positive and significant (P < 0.05) for primary branches plant⁻¹ vs seed yield plant⁻¹ (r = 0.3334^*), days to maturity vs spike length (r = 0.5384^**), days to 75% flowering vs days to 90% maturity (r = 0.4073^**), days to 75% flowering vs seed index (r = 0.4291^**), days to 90% maturity vs seed index (r = 0.3973^**) and seed index v/s seed yield plot⁻¹ (r = 0.5160^**). Negative and significant (P < 0.05) association was observed for primary branches plant⁻¹ vs days to maturity (r = −0.368^*), capsules plant⁻¹ vs days to maturity (r = −0.3567^*), days to 90% maturity vs seed yield plant⁻¹ (r = −0.4156^**) and days to 90% maturity vs seed yield plot⁻¹ (r = −0.3423^*). These results are further supported by Jain et al. [18] who observed significant variation in ten yield related traits in 28 hybrids of linseed and reported that highest variability in varieties was observed for capsules plant⁻¹ which guided the change in yield plant⁻¹ significantly. Khorgade and Pillai [19] , revealed the seeds plant⁻¹, capsules plant⁻¹, branches plant⁻¹ and seeds capsule⁻¹ was positively and significantly correlated with seed yield. Seeds plant⁻¹ and capsules plant⁻¹ showed a high positive direct effect on seed yield. They suggested that selection for seeds plant⁻¹ and capsules plants⁻¹ is important attributes to evolve high yielding varieties of linseed. Mishra et al. [20] , revealed the plant height exhibited negative direct association with seed yield. Path analysis revealed that plant height had a low association with number of branches and capsules per plant. Pal et al. [21] , also found that the number of days to 50% flowering, days to maturity number of primary branches plant⁻¹, number of capsules plant⁻¹, number seeds capsule⁻¹, 1000-seed weight had significant and positive correlation with seed yield plant⁻¹. Chimurkar et al. [22] , found that seed yield plant⁻¹ was positively and significantly correlated with number of branches plant⁻¹, number of capsules plant⁻¹ and 1000-seed weight but non-significantly and negatively correlated with plant height. Akbar et al. [23] , also reported that the growth and yield parameters like plant height, number of branches plant⁻¹, number of capsules plant⁻¹, 1000-seed weight, biological yield, seed yield, straw yield and harvest index were influenced significantly under various interactions of row spacing and genotypes, Ali et al. [8] compared the production potential of Linola and the traditional oilseed linseed Chandni under different nitrogen levels were he found significant differences in different traits of linola and linseed (chandni). Khan et al. [24] revealed the differences in mean yield performance of 10 linseed genotypes were highly significant during 6 years indicating presence of sufficient amount of variation among the genotypes. Khan et al. [25] revealed the sowing date had significant effect on plant height, number of capsule in plant, seed yield, Biomass, oil percent and oil yield in 1% level and on number of seed in capsule in 5% level of linseed. Ghanbari-odivi et al. [26] also revealed the confirmed results of the complex genetic architecture of yield-related traits and the inherent difficulties associated with their identification while illustrating the potential for improvement through marker-assisted selection of linseed.

The screening of some selected linseed genotypes for yield performance as well as associations amongst yield and its contributing traits were carried out during the year 2013-14. The experimental material comprised of eleven new linseed genotypes and a commercial check (Ilsi). The linseed genotypes included: L-53, C-W-2, Shikarpur 2, P⁻¹6-4, L-8, 11⁻¹06, Hala 3, L⁻¹7, Santane, Summit, L⁻¹0 and llsi 90 (Check). The mean squares drawn from the analysis of variance and performance was analysed in regards to days to 75% flowering, days to 90% maturity, plant height, primary branches plant⁻¹, seeds capsule⁻¹, capsules plant⁻¹, 1000 seed weight, seed yield plant⁻¹, seed yield plot⁻¹. The findings of the study are summarized as follows:

The analysis of variance suggested significant (P < 0.05) variation among linseed genotypes for days to 75% flowering, days to 90% maturity, plant height, primary branches plant⁻¹, seeds capsule⁻¹, capsules plant⁻¹, 1000 seed weight, seed yield plant⁻¹ and seed yield plot⁻¹. Linseed genotype L-8 took maximum days to 75% flowering (83.10) and minimum (77.84) by L-53 against 81.44 days by check variety Ilsi-90. Genotype 11⁻¹06 took more days to 90% maturity (118.10) and minimum (112.27) by L-53 against 117.73 days in Ilsi-90. The number of primary branches plant⁻¹ was highest (33.00) in genotype P⁻¹6-4 and the lowest (23.07) in Shikarpur-2 against 30.73 branches in Ilsi-90. More seeds capsule⁻¹ were noted in genotypes L-8 (9.67), L-53 (9.58), Hala-3 (9.51) and L⁻¹0 (9.15); and lowest in C-W-2 (8.20) against 8.55 seeds capsule⁻¹ in Ilsi-90.

The capsules plant⁻¹ was highest (221.07) in genotype L⁻¹0 and lowest (196.27) in P⁻¹6-4 against 213.40 in Ilsi-90. The seed index was highest in genotype P⁻¹6-4 (5.16 g) and minimum in genotype L-53 (4.57 g) against 5.16 g seed index in Ilsi-90. The seed yield plant⁻¹ was higher in genotypes P⁻¹6-4 (1.28 g), Summit (1.28 g), Hala-3 (1.27 g) and L-53 (1.26 g) against 0.71 g seed yield plant⁻¹ in Ilsi-90 and lowest (0.48 g) in 11⁻¹06. The seed yield plot⁻¹ was highest in genotypes P⁻¹6-4 (0.81 kg) and lowest in Shikarpur-2 (0.55 kg) against 0.50 kg in Ilsi-90. This indicates that all the genotypes tested in this experiment such as L-53, C-W-2, Shikarpur 2, P⁻¹6-4, L-8, 11⁻¹06, Hala 3, L⁻¹7, Santane, Summit, L⁻¹0 surpassed the commercial check variety Ilsi-90 for seed yield plot⁻¹. It can be clearly noticed from the agronomic performance of the new genotypes that these varieties possess the potential to become future varieties for general cultivation in Sindh province.

The correlation coefficient for yield and its contributing traits of linseed genotypes showed a positive and significant (P < 0.05) association for primary branches plant⁻¹ vs seed yield plant⁻¹ (r = 0.3334^*), days to maturity vs spike length (r = 0.5384^**), days to 75% flowering vs days to 90% maturity (r = 0.4073^**), days to 75% flowering vs seed index (r = 0.4291^**), days to 90% maturity vs seed index (r = 0.3973^**) and seed index v/s seed yield plot⁻¹ (r = 0.5160^**). Negative and significant (P < 0.05) association was observed for primary branches plant⁻¹ vs days to maturity (r = −0.368^*), capsules plant⁻¹ vs days to maturity (r = −0.3567^*), days to 90% maturity vs seed yield plant⁻¹ (r = −0.4156^**) and days to 90% maturity vs seed yield plot⁻¹ (r = −0.3423^*).

Non-significant and positive (P > 0.05) association was calculated for plant height vs primary branches plant⁻¹ (r = 0.0.1164^NS), Plant height vs number of seeds capsule⁻¹ (r = 0.2804^NS), Plant height vs days to 75% flowering (r = 0.3093^NS), Plant height vs days to 90% maturity (r = 0.1248^NS), Primary branches plant⁻¹ vs seeds capsule⁻¹ (r = 0.2087^NS), Primary branches plant⁻¹ vs days to flowering (r = 0.0490^NS), Primary branches plant⁻¹ vs seed index (r = 0.2744^NS), Primary branches plant⁻¹ vs Seed yield plot⁻¹ (r = 0.2428^NS),capsules plant⁻¹ vs days to flowering (r = 0.0451^NS), capsules plant⁻¹ vs seed index (r = 0.0747^NS), Capsules plant⁻¹ vs Seed yield plant⁻¹ (r = 0.2605^NS), Seeds capsule⁻¹ vs Days to flowering (r = −0.2795^NS), Seeds capsule⁻¹ vs seed index (r = 0.0609^NS), Seeds capsule⁻¹ vs Seed yield plot⁻¹ (r = 0.0065^NS), Days to 75% flowering vs seed yield plant⁻¹ (r = 0.3076^NS), Days to 75% flowering vs seed yield plot⁻¹ (r = 0.0949^NS), Seed index vs seed yield plant⁻¹ (r = 0.1837^NS), Seed yield plant⁻¹ vs seed yield plot⁻¹ (r = 0.2890^NS).

Non-significant and negative (P > 0.05) association was observed for Plant height vs number of capsules plant⁻¹ (r = −0.2587^NS), Plant height vs seed index (r = −0.0628^NS), Plant height vs Yield plant⁻¹ (r = −0.1353^NS), Plant height vs seed yield plot⁻¹ (r = −0.0001^NS), Primary branches plant⁻¹ vs capsules plant⁻¹ (r = −0.0356^NS), Capsules plant⁻¹ vs Seeds capsule⁻¹ (r = −0.0304^NS), Capsules plant⁻¹ vs days to maturity (r = −0.0833^NS) and Seeds capsule⁻¹ vs Days to flowering (r = −0.2795^NS).

Shoaib Gul,Asghar Ali Rajper,Fahad Ali Kalhoro,Shamir Ali Kalhoro,Amjad Ali,Fayaz Ali Shah,Sajjad Raza,Muneer Ahmed, (2016) Screening Selected Linseed (Linum usitatissimum L.) Genotypes for Yield Performance in Sindh, Pakistan. Natural Science,08,53-65. doi: 10.4236/ns.2016.82007