<p>Genetic divergence among parents is essential for the expression of heterosis of enlarging variability in the subsequent segregating generations. Generally, genotypes drawn from diverse geographical regions are preferred in the hybridization programmes, on the presumption that genetic diversity is parallel to geographical diversity. Pumpkin (<italic>Cucurbita morchatus Duch</italic>. ex. Poir.) is an important cucurbitaceous vegetable crop because of higher vitamin A and better keeping quality of fruits. Precise information on the nature and degree of genetic divergence would help the plant breeder in choosing the right type of parents for purposeful hybridization programme.</p><p>The genetic divergence among 50 germplasm lines of pumpkin was studied using method of nonhierarchical Euclidean cluster analysis as described by Beale (<xref ref-type="bibr" rid="bib002">2</xref>). Fitness of the cluster arrangement was judge by sequential F-ratio test. The pseudo-F-statistics was computed and found highly significant for second and third cluster. Therefore, grouping with three clusters was regarded as appropriate.</p><p>In the present study, all the 50 genotypes were grouped into three different clusters (<xref ref-type="table" rid="tab001">Table 1</xref>). Cluster I accommodated the highest number of 25 genotypes, whereas cluster III and II had 20 and 5 genotypes respectively. Intracluster distances were found as 2.19 for cluster 1, 3.33 for cluster III and 4.22 for cluster II. Maximum inter-cluster distance values (6.91) was recorded between cluster I and III (<xref ref-type="table" rid="tab002">Table 2</xref>). Babu <italic>et al.</italic> (<xref ref-type="bibr" rid="bib001">1</xref>) and Kale <italic>et al.</italic> (<xref ref-type="bibr" rid="bib004">4</xref>) reported similarly for genetic diversity in pumpkin. Several workers found similar results for genetic diversity in various cucurbits like Wahab and Gopalkrishan (<xref ref-type="bibr" rid="bib008">8</xref>) in bittergourd; Dora <italic>et al.</italic> (<xref ref-type="bibr" rid="bib003">3</xref>) and Mathew <italic>et al.</italic> (<xref ref-type="bibr" rid="bib006">6</xref>) in bottlegourd, and Ram <italic>et al.</italic> (<xref ref-type="bibr" rid="bib007">7</xref>) in pointed gourd. Genotypes belonging to cluster with maximum inter-cluster distance are genetically more divergent and hybridization between genotypes of divergent cluster is likely to produce wide variability. The critical perusal of the results obtained from the present investigation also revealed similar finding, i.e. distribution of the genotypes was not according to the geographical location, but geographically all these districts belong to same region of eastern UP. For examples, the lines PPU-138, PPU-140 (Deoria), PPU Genetic 144 (Pacirauna), PPU-147 (Kushinagar) and PPU-151 (Gorakhpur) belonged to different locations, but grouped into same cluster (<xref ref-type="bibr" rid="bib001">1</xref>) and the lines PPU-156 and PPU-157 belonged to same location (Chanipawat), but occupied different groups, I and III respectively. Kalloo <italic>et al.</italic> (<xref ref-type="bibr" rid="bib005">5</xref>) suggested that geographical origin is not a single factor for genetic divergence in muskmelon. Most of the superior genotypes were confined to cluster I, while cluster II accommodated similar type of lines (PPU-155, PPU-159, PPU-162, PPU 177 and PPU-196) having long cylindrical fruits. <table-wrap id="tab001"><label>Table 1</label><caption><p>Grouping of fifty genotypes of pumpkin in different clusters.</p></caption><table><thead><tr><th align="center">Cluters number</th><th align="center">Number</th><th>Genotypes</th></tr></thead><tbody><tr><td colspan="3"><hr /></td></tr><tr><td align="center" valign="top">1</td><td align="center" valign="top">25</td><td>PPU-138, PPU-139, PPU-140, PPU-141, PPU-142, PPU-143, PPU-144,PPU-145, PPU-146, PPU-147, PPU-148, PPU-149, PPU-150, PPU-151,PPU-152, PPU-153, PPU-154, PPU-156, PPU-158, PPU-178, PPU-182,PPU-184, PPU-185, PPU-188, PPU-190</td></tr><tr><td align="center" valign="top">II</td><td align="center" valign="top">5</td><td>PPU-155, PPU-159, PPU-162, PPU-177, PPU-196</td></tr><tr><td align="center" valign="top">III</td><td align="center" valign="top">20</td><td>PPU-157, PPU-161, PPU-168, PPU-170, 173, PPU-174, PPU-175, PPU-176, PPU-180, PPU-181, PPU-183,PPU-186, PPU-187, PPU-189, PPU-191, PPU-192, PPU-193, PPU-194,PPU-195, PPU-197</td></tr></tbody></table></table-wrap><table-wrap id="tab002"><label>Table 2</label><caption><p>Average intra- and inter-cluster distance values.</p></caption><table><thead><tr><th align="center">Cluster</th><th align="center">1</th><th align="center">II</th><th align="center">III</th></tr></thead><tbody><tr><td colspan="4"><hr /></td></tr><tr><td align="center">1</td><td align="center">2.19</td><td /><td /></tr><tr><td align="center">II</td><td align="center">6.91</td><td align="center">4.22</td><td /></tr><tr><td align="center">III</td><td align="center">4.68</td><td align="center">6.18</td><td align="center">3.33</td></tr></tbody><tfoot><tr><td colspan="4"><hr /></td></tr><tr><td colspan="4">Values in bold show intra-cluster distances.</td></tr></tfoot></table></table-wrap></p><p>Cluster I showed least values for days to anthesis of first male flower, days to anthesis of first female flower and node number at first female flower (<xref ref-type="table" rid="tab003">Table 3</xref>). It showed highest values for yield, fruit diameter, fruit number/plant, number of ridges, flesh thickness, peduncle length, peduncle depression length and width and vine length. The highest values were observed in fruit length and seed cavity depth for cluster II. While node number at first male flower had minimum value. While cluster III showed the highest values only for seed cavity length and seed cavity width. <table-wrap id="tab003"><label>Table 3</label><caption><p>Cluster mean and standard deviation values for different characters in pumpkin genotypes.</p></caption><table><thead><tr><th rowspan="3">Character</th><th colspan="3" align="center">Cluster means value</th><th colspan="3" align="center">Cluster standard deviation</th></tr><tr><th colspan="3"><hr /></th><th colspan="3"><hr /></th></tr><tr><th align="center">1</th><th align="center">II</th><th align="center">III</th><th align="center">I</th><th align="center">II</th><th align="center">III</th></tr></thead><tbody><tr><td colspan="7"><hr /></td></tr><tr><td>Days to anthesis of 1st male flower</td><td align="center">48.96</td><td align="center">51.80</td><td align="center">57.19</td><td align="center">1.79</td><td align="center">2.39</td><td align="center">6.89</td></tr><tr><td>Days to anthesis of 1st female flower</td><td align="center">51.93</td><td align="center">55.00</td><td align="center">63.19</td><td align="center">1.52</td><td align="center">1.87</td><td align="center">10.92</td></tr><tr><td>Node no. to 1st male flower</td><td align="center">3.51</td><td align="center">3.12</td><td align="center">4.90</td><td align="center">0.41</td><td align="center">0.46</td><td align="center">0.59</td></tr><tr><td>Node no. to Ist female flower</td><td align="center">16.02</td><td align="center">16.32</td><td align="center">3.54</td><td align="center">1.98</td><td align="center">6.54</td><td align="center">3.05</td></tr><tr><td>Fruit length (cm)</td><td align="center">20.86</td><td align="center">21.92</td><td align="center">15.81</td><td align="center">2.98</td><td align="center">7.91</td><td align="center">2.40</td></tr><tr><td>Fruit diameter (cm)</td><td align="center">22.19</td><td align="center">10.12</td><td align="center">17.62</td><td align="center">2.17</td><td align="center">1.01</td><td align="center">1.89</td></tr><tr><td>No. of fruits/plant</td><td align="center">6.29</td><td align="center">6.12</td><td align="center">4.66</td><td align="center">0.49</td><td align="center">1.54</td><td align="center">0.81</td></tr><tr><td>No. of ridges/fruit</td><td align="center">20.06</td><td align="center">0.00</td><td align="center">15.68</td><td align="center">2.54</td><td align="center">0.00</td><td align="center">1.85</td></tr><tr><td>Fruit flesh thickness (cm)</td><td align="center">4.71</td><td align="center">1.98</td><td align="center">3.79</td><td align="center">0.72</td><td align="center">0.67</td><td align="center">0.47</td></tr><tr><td>Seed cavity length (cm)</td><td align="center">16.79</td><td align="center">6.54</td><td align="center">19.13</td><td align="center">3.79</td><td align="center">1.34</td><td align="center">5.85</td></tr><tr><td>Seed cavity width (cm)</td><td align="center">15.81</td><td align="center">6.50</td><td align="center">19.10</td><td align="center">2.71</td><td align="center">1.26</td><td align="center">5.49</td></tr><tr><td>Seed cavity depth (cm)</td><td align="center">13.05</td><td align="center">17.92</td><td align="center">15.75</td><td align="center">3.12</td><td align="center">9.30</td><td align="center">5.41</td></tr><tr><td>Peduncle length (cm)</td><td align="center">8.89</td><td align="center">7.22</td><td align="center">7.70</td><td align="center">0.59</td><td align="center">3.21</td><td align="center">0.83</td></tr><tr><td>Peduncle depression length (cm)</td><td align="center">4.87</td><td align="center">3.92</td><td align="center">4.11</td><td align="center">0.45</td><td align="center">1.25</td><td align="center">0.63</td></tr><tr><td>Peduncle depression width (cm)</td><td align="center">3.64</td><td align="center">2.32</td><td align="center">2.76</td><td align="center">0.43</td><td align="center">0.77</td><td align="center">0.65</td></tr><tr><td>Vine length (m)</td><td align="center">6.66</td><td align="center">4.98</td><td align="center">4.95</td><td align="center">0.64</td><td align="center">0.76</td><td align="center">1.23</td></tr><tr><td>Fruit yield (q/ha)</td><td align="center">170.93</td><td align="center">42.20</td><td align="center">116.07</td><td align="center">42.75</td><td align="center">6.18</td><td align="center">36.34</td></tr></tbody></table></table-wrap></p><p>Clusters standard deviation was calculated and it showed considerable differences among the clusters for all the characters. Cluster III showed the maximum standard deviation for the characters like days to anthesis of first male flower, days to anthesis of first female flower, node number to first male flower, seed cavity length, seed cavity width and vine length. The characters like fruit yield, fruit diameter number of ridges and fruit thickness were found with maximum deviation in cluster I. The highest standard deviation was obtained in cluster II for the days to anthesis of first female flower, fruit number, seed cavity depth, peduncle length, peduncle depression length and peduncle depression width.</p></sec></body><back><ref-list><title>References

IJH

Indian Journal of Horticulture

0972-8538

The Horticultural Society of India

ijh-63-1-028

RESEARCH NOTE

Genetic diversity in indigenous germplasm of pumpkin

Kumar

Jagesh

Singh

D.K.

*Har Ram

Hari

Department of Vegetable Science, G.B. Pant University of Agriculture and Technology, Pantnagar 263 145, Uttaranchal

*Corresponding author

32006

63110110292004102005112005

<p>Genetic divergence among parents is essential for the expression of heterosis of enlarging variability in the subsequent segregating generations. Generally, genotypes drawn from diverse geographical regions are preferred in the hybridization programmes, on the presumption that genetic diversity is parallel to geographical diversity. Pumpkin (<italic>Cucurbita morchatus Duch</italic>. ex. Poir.) is an important cucurbitaceous vegetable crop because of higher vitamin A and better keeping quality of fruits. Precise information on the nature and degree of genetic divergence would help the plant breeder in choosing the right type of parents for purposeful hybridization programme.</p><p>The genetic divergence among 50 germplasm lines of pumpkin was studied using method of nonhierarchical Euclidean cluster analysis as described by Beale (<xref ref-type="bibr" rid="bib002">2</xref>). Fitness of the cluster arrangement was judge by sequential F-ratio test. The pseudo-F-statistics was computed and found highly significant for second and third cluster. Therefore, grouping with three clusters was regarded as appropriate.</p><p>In the present study, all the 50 genotypes were grouped into three different clusters (<xref ref-type="table" rid="tab001">Table 1</xref>). Cluster I accommodated the highest number of 25 genotypes, whereas cluster III and II had 20 and 5 genotypes respectively. Intracluster distances were found as 2.19 for cluster 1, 3.33 for cluster III and 4.22 for cluster II. Maximum inter-cluster distance values (6.91) was recorded between cluster I and III (<xref ref-type="table" rid="tab002">Table 2</xref>). Babu <italic>et al.</italic> (<xref ref-type="bibr" rid="bib001">1</xref>) and Kale <italic>et al.</italic> (<xref ref-type="bibr" rid="bib004">4</xref>) reported similarly for genetic diversity in pumpkin. Several workers found similar results for genetic diversity in various cucurbits like Wahab and Gopalkrishan (<xref ref-type="bibr" rid="bib008">8</xref>) in bittergourd; Dora <italic>et al.</italic> (<xref ref-type="bibr" rid="bib003">3</xref>) and Mathew <italic>et al.</italic> (<xref ref-type="bibr" rid="bib006">6</xref>) in bottlegourd, and Ram <italic>et al.</italic> (<xref ref-type="bibr" rid="bib007">7</xref>) in pointed gourd. Genotypes belonging to cluster with maximum inter-cluster distance are genetically more divergent and hybridization between genotypes of divergent cluster is likely to produce wide variability. The critical perusal of the results obtained from the present investigation also revealed similar finding, i.e. distribution of the genotypes was not according to the geographical location, but geographically all these districts belong to same region of eastern UP. For examples, the lines PPU-138, PPU-140 (Deoria), PPU Genetic 144 (Pacirauna), PPU-147 (Kushinagar) and PPU-151 (Gorakhpur) belonged to different locations, but grouped into same cluster (<xref ref-type="bibr" rid="bib001">1</xref>) and the lines PPU-156 and PPU-157 belonged to same location (Chanipawat), but occupied different groups, I and III respectively. Kalloo <italic>et al.</italic> (<xref ref-type="bibr" rid="bib005">5</xref>) suggested that geographical origin is not a single factor for genetic divergence in muskmelon. Most of the superior genotypes were confined to cluster I, while cluster II accommodated similar type of lines (PPU-155, PPU-159, PPU-162, PPU 177 and PPU-196) having long cylindrical fruits. <table-wrap id="tab001"><label>Table 1</label><caption><p>Grouping of fifty genotypes of pumpkin in different clusters.</p></caption><table><thead><tr><th align="center">Cluters number</th><th align="center">Number</th><th>Genotypes</th></tr></thead><tbody><tr><td colspan="3"><hr /></td></tr><tr><td align="center" valign="top">1</td><td align="center" valign="top">25</td><td>PPU-138, PPU-139, PPU-140, PPU-141, PPU-142, PPU-143, PPU-144,PPU-145, PPU-146, PPU-147, PPU-148, PPU-149, PPU-150, PPU-151,PPU-152, PPU-153, PPU-154, PPU-156, PPU-158, PPU-178, PPU-182,PPU-184, PPU-185, PPU-188, PPU-190</td></tr><tr><td align="center" valign="top">II</td><td align="center" valign="top">5</td><td>PPU-155, PPU-159, PPU-162, PPU-177, PPU-196</td></tr><tr><td align="center" valign="top">III</td><td align="center" valign="top">20</td><td>PPU-157, PPU-161, PPU-168, PPU-170, 173, PPU-174, PPU-175, PPU-176, PPU-180, PPU-181, PPU-183,PPU-186, PPU-187, PPU-189, PPU-191, PPU-192, PPU-193, PPU-194,PPU-195, PPU-197</td></tr></tbody></table></table-wrap><table-wrap id="tab002"><label>Table 2</label><caption><p>Average intra- and inter-cluster distance values.</p></caption><table><thead><tr><th align="center">Cluster</th><th align="center">1</th><th align="center">II</th><th align="center">III</th></tr></thead><tbody><tr><td colspan="4"><hr /></td></tr><tr><td align="center">1</td><td align="center">2.19</td><td /><td /></tr><tr><td align="center">II</td><td align="center">6.91</td><td align="center">4.22</td><td /></tr><tr><td align="center">III</td><td align="center">4.68</td><td align="center">6.18</td><td align="center">3.33</td></tr></tbody><tfoot><tr><td colspan="4"><hr /></td></tr><tr><td colspan="4">Values in bold show intra-cluster distances.</td></tr></tfoot></table></table-wrap></p><p>Cluster I showed least values for days to anthesis of first male flower, days to anthesis of first female flower and node number at first female flower (<xref ref-type="table" rid="tab003">Table 3</xref>). It showed highest values for yield, fruit diameter, fruit number/plant, number of ridges, flesh thickness, peduncle length, peduncle depression length and width and vine length. The highest values were observed in fruit length and seed cavity depth for cluster II. While node number at first male flower had minimum value. While cluster III showed the highest values only for seed cavity length and seed cavity width. <table-wrap id="tab003"><label>Table 3</label><caption><p>Cluster mean and standard deviation values for different characters in pumpkin genotypes.</p></caption><table><thead><tr><th rowspan="3">Character</th><th colspan="3" align="center">Cluster means value</th><th colspan="3" align="center">Cluster standard deviation</th></tr><tr><th colspan="3"><hr /></th><th colspan="3"><hr /></th></tr><tr><th align="center">1</th><th align="center">II</th><th align="center">III</th><th align="center">I</th><th align="center">II</th><th align="center">III</th></tr></thead><tbody><tr><td colspan="7"><hr /></td></tr><tr><td>Days to anthesis of 1st male flower</td><td align="center">48.96</td><td align="center">51.80</td><td align="center">57.19</td><td align="center">1.79</td><td align="center">2.39</td><td align="center">6.89</td></tr><tr><td>Days to anthesis of 1st female flower</td><td align="center">51.93</td><td align="center">55.00</td><td align="center">63.19</td><td align="center">1.52</td><td align="center">1.87</td><td align="center">10.92</td></tr><tr><td>Node no. to 1st male flower</td><td align="center">3.51</td><td align="center">3.12</td><td align="center">4.90</td><td align="center">0.41</td><td align="center">0.46</td><td align="center">0.59</td></tr><tr><td>Node no. to Ist female flower</td><td align="center">16.02</td><td align="center">16.32</td><td align="center">3.54</td><td align="center">1.98</td><td align="center">6.54</td><td align="center">3.05</td></tr><tr><td>Fruit length (cm)</td><td align="center">20.86</td><td align="center">21.92</td><td align="center">15.81</td><td align="center">2.98</td><td align="center">7.91</td><td align="center">2.40</td></tr><tr><td>Fruit diameter (cm)</td><td align="center">22.19</td><td align="center">10.12</td><td align="center">17.62</td><td align="center">2.17</td><td align="center">1.01</td><td align="center">1.89</td></tr><tr><td>No. of fruits/plant</td><td align="center">6.29</td><td align="center">6.12</td><td align="center">4.66</td><td align="center">0.49</td><td align="center">1.54</td><td align="center">0.81</td></tr><tr><td>No. of ridges/fruit</td><td align="center">20.06</td><td align="center">0.00</td><td align="center">15.68</td><td align="center">2.54</td><td align="center">0.00</td><td align="center">1.85</td></tr><tr><td>Fruit flesh thickness (cm)</td><td align="center">4.71</td><td align="center">1.98</td><td align="center">3.79</td><td align="center">0.72</td><td align="center">0.67</td><td align="center">0.47</td></tr><tr><td>Seed cavity length (cm)</td><td align="center">16.79</td><td align="center">6.54</td><td align="center">19.13</td><td align="center">3.79</td><td align="center">1.34</td><td align="center">5.85</td></tr><tr><td>Seed cavity width (cm)</td><td align="center">15.81</td><td align="center">6.50</td><td align="center">19.10</td><td align="center">2.71</td><td align="center">1.26</td><td align="center">5.49</td></tr><tr><td>Seed cavity depth (cm)</td><td align="center">13.05</td><td align="center">17.92</td><td align="center">15.75</td><td align="center">3.12</td><td align="center">9.30</td><td align="center">5.41</td></tr><tr><td>Peduncle length (cm)</td><td align="center">8.89</td><td align="center">7.22</td><td align="center">7.70</td><td align="center">0.59</td><td align="center">3.21</td><td align="center">0.83</td></tr><tr><td>Peduncle depression length (cm)</td><td align="center">4.87</td><td align="center">3.92</td><td align="center">4.11</td><td align="center">0.45</td><td align="center">1.25</td><td align="center">0.63</td></tr><tr><td>Peduncle depression width (cm)</td><td align="center">3.64</td><td align="center">2.32</td><td align="center">2.76</td><td align="center">0.43</td><td align="center">0.77</td><td align="center">0.65</td></tr><tr><td>Vine length (m)</td><td align="center">6.66</td><td align="center">4.98</td><td align="center">4.95</td><td align="center">0.64</td><td align="center">0.76</td><td align="center">1.23</td></tr><tr><td>Fruit yield (q/ha)</td><td align="center">170.93</td><td align="center">42.20</td><td align="center">116.07</td><td align="center">42.75</td><td align="center">6.18</td><td align="center">36.34</td></tr></tbody></table></table-wrap></p><p>Clusters standard deviation was calculated and it showed considerable differences among the clusters for all the characters. Cluster III showed the maximum standard deviation for the characters like days to anthesis of first male flower, days to anthesis of first female flower, node number to first male flower, seed cavity length, seed cavity width and vine length. The characters like fruit yield, fruit diameter number of ridges and fruit thickness were found with maximum deviation in cluster I. The highest standard deviation was obtained in cluster II for the days to anthesis of first female flower, fruit number, seed cavity depth, peduncle length, peduncle depression length and peduncle depression width.</p></sec></body><back><ref-list><title>References1

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V.S.

Gopalakrishnan

T.R.

Peter

K.V.

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Beale

E.M.L.

1969. Euclidean cluster analysis. Bull. Int. Stat. Inst. 43: 92–94.3

Dora

D.K.

Archarya

G.C.

Das

2001. Genetic divergence in pointed gourd (Trichosanthes dioica Roxb). Veg. Sci. 28: 170–71.4

Kale

V.S.

Patil

B.R.

Bindu

Paithankar

D.H.

2002. Genetic divergence in pumpkin (Cucurbita moschata). J. Soil Crops, 12: 213–16.5

Kalloo

Dixit

Sidhu

A.S.

1982. Genetic divergence in muskmelon (Cucumis melo L.). Genetica Agrarian, 36: 1–7.6

Mathew

Morkose

B.L.

Rajan

Devi

2001. Genetic divergence in bottlegourd. Veg. Sci. 28: 121–23.7

Ram

Kalloo

Singh

2001. Cluster analysis in pointed gourd (Trichosanthes dioica Roxb). Veg. Sci. 28: 67–68.8

Wahab

M.A.

Gopalakrishnan

P.K.

1993. Genetic divergence in bittergourd (Momordica charantia L.). South Indian Hort. 41: 232–34.