The simple correlation coefficients between yield and various yield components and inter-relationship among the traits were computed and they are presented in Table 1. Spike yield per plant showed positive and significant association with plant height (0.33), rachis length (0.30), number of florets per spike (0.34), weight of single floret (0.63), matured bud weight (0.66), duration of flowering (0.52) and high negative correlation with days to spike appearance (-0.84). Flower yield is a complex trait, the expression of which depends on the action and multiple interactions of various components. The associations of these characters with flower yield per plant are in desirable direction and selection of these traits may ultimately improve the yield. The results are in line with the findings of
Kannan et al., (1998), Nagaraja and Gowda (2002),
Ranchana et al., (2015), Gaidhani et al., (2016) in tuberose and
Kameswari et al., (2015) in chrysanthemum.
Plant height showed positive and significant association with number of florets per spike (0.36), weight of single floret (0.47), matured bud weight (0.59).
Kumar et al., (2011) reported significant and positive association of plant height with spike length in gladiolus and the results are in line with findings of
Ranchana et al., (2015) in tuberose. Number of leaves per clump showed positive correlation with floret tube length (0.38). This is in consonance with the findings of
Vetrivel (2010),
Kumar et al., (2012) in gladiolus and Ranchana
et al. (2015) in tuberose. Days to spike appearance showed significant negative correlation with number of florets per spike (-0.40), length of the floret (-0.35), weight of single floret (-0.50), matured bud weight (-0.56) and duration of flowering (-0.49). Similar findings were also reported by
Vetrivel (2010),
Kumar et al., (2011) in gladiolus and
Ranchana et al., (2015) in tuberose.
Spike length has significant positive association with floret tube length (0.40) and weight of single floret (0.33). A significant positive association between spike length, plant height and number of florets was evidenced by
Anuradha and Gowda, (2000) in gladiolus.
Ranchana et al., (2015) also reported that the length of the floret and number of florets per spike had significant but negative correlation with spike length. Rachis length showed significant positive correlation with length of the floret (0.52), diameter of the floret (0.69), weight of single floret (0.81), matured bud weight (0.72) and duration of flowering (0.59). Findings derive support from the results of
Kumar et al., (2012) in snapdragon and
Ranchana et al., (2015) in tuberose.
Length of the floret showed positive correlation with flower tube length (0.57), diameter of the floret (0.79), weight of single floret (0.60), matured bud weight (0.59) and duration of flowering (0.50). This is in accordance with the findings of
Ranchana et al., (2015) in tuberose. A significant and positive correlation between leaf area and floret length was noted in gladiolus by
Zorana et al., (2011) and
Aasia et al., (2016). Floret tube length had significant positive association with weight of single floret (0.35). Diameter of the floret showed positive correlation with weight of single floret (0.66), matured bud weight (0.64) and duration of flowering (0.53). Weight of single floret showed positive correlation with matured bud weight (0.97) and duration of flowering (0.68). Matured bud weight had significant positive association with duration of flowering (0.68). The results derive the support from the findings of
Bharathi et al., (2014) in marigold.
Path coefficient analysis
The genotypic correlation co-efficient of single tuberose genotypes was apportioned into direct effects and indirect effects by path analysis and the results are presented in Table 2. The residual effect (0.342) indicated that most of the yield contributing characters was included in the study. The path coefficient analysis was studied for 13 characters which indicated that the weight of the floret (1.48) had very high positive direct effect on spike yield per plant followed by length of the floret (0.84) number of florets per spike (0.45) and duration of flowering (0.41) which had high positive direct effect, spike length (0.27) had moderate positive direct effect, plant height (0.16) and number of leaves (0.17) showed low positive direct effect and rest of the characters had negligible positive direct effect on spike yield per plant. Similar results were recorded by
Kannan et al., (1998) in tuberose. Matured bud weight (-1.40) had very high negative direct effect on spike yield per plant followed by diameter of the floret (-0.78), flower tube length (-0.70), days to appearance (-0.36) which showed high negative direct effect on spike yield per plant. Similar such findings were reported by
Kannan et al., (1998), Saravanakumar (2000) and
Ranchana et al., (2015) in tuberose.
Plant height recorded very high positive indirect effect through weight of single floret (0.71) and low indirect through days to spike appearance (0.11), number of florets per spike (0.17) and length of the floret (0.10). Negligible influence was exhibited through number of leaves (0.02), spike length (0.08), rachis length (0.02) and duration of flowering (0.07) whereas other characters exerted negative indirect effect. Results are in consonance with the findings of
Ranchana et al., (2015) in tuberose. Number of leaves evidenced low positive indirect effect on spike yield per plant through length of the floret (0.15) and negligible positive indirect effect through plant height (0.01), days to spike appearance (0.07), spike length (0.01), diameter of the floret (0.04), matured bud weight (0.07) and duration of flowering (0.00) whereas other characters showed negative effect. In contradiction to this
Ranchana et al., (2015) recorded strong positive indirect effect through plant height, spike length and duration of flowering in tuberose.
Days to spike appearance recorded very high positive indirect effect through matured bud weight (0.79), low indirect effect through floret tube length (0.11) and diameter of the floret (0.12) and negligible positive effect through spike length (0.01) whereas other characters exerted negative indirect effect.
Spike length showed high positive indirect effect through weight of single floret (0.49), low positive indirect effect through length of the floret (0.14), negligible indirect effect through plant height (0.04), number of leaves (0.00), rachis length (0.02) and duration of flowering (0.03) whereas other characters exhibited negative indirect effect. Similar observations were recorded by
Vetrivel (2010) in gladiolus and
Ranchana et al., (2015) in tuberose. Rachis length recorded very high positive indirect effect through weight of single floret (1.24) and length of the floret (0.47) showed high positive indirect effect, moderate effect was shown by duration of flowering (0.25) and negligible positive indirect effect through plant height (0.04), days to spike appearance(0.04) and spike length (0.07) whereas other characters showed negative indirect effect. Similar observations were also recorded by
Ranchana et al., (2015).
Number of florets per spike recorded high positive indirect effect for spike yield per plant through weight of single floret (0.32) and low negative effect through days to spike appearance (0.14). Negligible positive indirect effect through plant height (0.06) and flower tube length (0.04) whereas other characters showed negligible positive and negative indirect effect. Results of the present study derive support from the findings of
Ranchana et al., (2015) in tuberose. Length of the floret recorded very high positive indirect effect through weight of single floret (0.88), moderate effect through duration of flowering (0.21), low positive indirect effect through days to spike appearance (0.13) and negligible positive effect through plant height (0.01), number of leaves (0.03), spike length (0.04) and rachis length (0.05) while other characters showed negative indirect effect. Results are in consonance with the findings of
Ranchana et al., (2015) in tuberose.
Floret tube length floret recorded high positive indirect effect through weight of single floret (0.55), length of floret (0.53) and low positive effect through duration of flowering (0.14), spike length (0.11), negligible positive indirect effect through plant height (0.01), number of leaves per clump (0.07), days to spike appearance (0.05) and rachis length (0.02) whereas other characters showed negative indirect effect. Diameter of the floret recorded high positive indirect effect through weight of single floret (0.98), length of the floret (0.67), moderate effect through duration of flowering (0.23) and negligible positive effect through plant height (0.04), days to spike appearance (0.05), spike length (0.02), rachis length (0.06) and number of florets per spike (0.07) while other characters showed negative indirect effect.
Weight of single floret recorded high positive indirect effect through length of the floret (0.50), moderate positive effect through duration of flowering (0.29), low positive effect through days to spike appearance (0.18), number of florets per spike (0.10) and negligible positive effect through plant height (0.07), spike length (0.09) and rachis length (0.07) whereas other characters showed negative indirect effect. Matured bud weight recorded very high positive indirect effect through weight of the single floret (1.44), high positive indirect effect through length of the floret (0.49), moderate high positive indirect effect through days to spike appearance (0.20), duration of flowering (0.29) low positive indirect effect was shown by number of florets per spike (0.13) whereas other characters showed negative indirect effect. Duration of flowering recorded very high positive indirect effect through weight of single floret (1.06), high positive indirect effect was recorded by length of the floret (0.44), low positive indirect effect was exhibited by days to spike appearance (0.18) whereas other characters showed negative indirect effect. This is in consonance with the findings of
Ranchana et al., (2015) and
Saravanakumar (2000).