Investigation the viability of pollen grains in some commercial hazelnut cultivars




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Investigation the viability of pollen grains in some commercial hazelnut cultivars

F.Bashiri Nazar1, S.Hossein Ava, 2, A.Imani3,V.Abdossi4

1, 4. Department of Agriculture and natural resource, Group of Horticulture, science and researches campus, Azad University Tehran, Iran.

2, 3. Horticultural research Department, Seed and Plant improvement Institute, (S.P.I.I.), Karaj-Iran.

Abstract

Pollen viability was studied in 5 commercial cultivars of the hazelnut (Corylus avellana L.) including Daviana, Paeezeh, Tabestaneh, Asli gharebagh, Anbooh during 2009-2010 in laboratory of Horticultural research Department, Seed and Plant improvement Institute. Pollen of five hazelnut cultivars were cultured to identify the best condition for maintain the Pollen viability for hand pollination. Pollens were cultured in medium contain 15% sucrose and 2% agar and effects of time and temperature were investigated in this experiment. Stored pollen viability at 4 ºC and 20ºC, unto 20 days has been good pollen.



Keywords: Pollen grain, hazelnut, germination, viability, pollination

Introduction

Hazelnut (Corylus avellana L.) is monoecious, , self-incompatible and wind-pollination (Lagerstedt, 1975; Thompson, 1979).The nuts of Hazelnut (Corylus avellana L.) exhibits several unusual characteristics such as fruit drop and kernelless fruits(Hossin-Ava et al. 2006). Incompatibility and dichogamy seems to be 2 main factors for these phenomena ((Thompson et al., 1996, Me et al., 2000) which are necessary to be inconsideration in breeding programs. Schuster(1924) and Johansson (1927) firstly showed the Incompatibility in cultivated hazelnuts (Corylus avellana L.). Single S-locus with multiple alleles are caused sporophytic self-incompatibility in Hazelnuts (Thompson,1979, Thompson, 1979).Incompatibility take place if the alleles in the pollen and pistil are identical.

During the stages of pollination of hazelnut it is possible to observe male and female inflorescences are not ripening together and shown the effect which are known as Dichogamy (Thompson et al., 1996).

For having better fruit set is the gathering the pollen grains from male flowers in the best time and crossing them with female flowers in the time which they have best condition for receipting the pollen(Erdouan et al., 2005).

. In general, compounds in the pollen medium at different concentrations are found. In addition, temperature of growth medium is an important factor that germination and growth are affected (Janick and Moore,1996)

To the best of our knowledge there are a few reports on the investigation of the best condition for maintaining pollen in hazelnut for handing pollination. Therefore the studding for optimization of these conditions for some commercial hazelnut cultivars is necessary. Object of research was investigation the stored pollen viability at 4 ºC and 20 ºC in deferent times.



Materials and methods

Viability of five hazelnut cultivars including daviana, paeezeh, tabestaneh, asli gharebagh and anbooh were examined in 2009-2010 in Karaj- Iran.

In this study when staminate catkins elongated and were about to shed pollen, they were collected, placed on sheet of paper in the laboratory, and allowed to dry overnight at room temperature (18-20°C). The following day, the pollens were gathered and separated with a metal grid. Half of collection pollens were stored in freezer (4°C) and half of them were placed in room temperature (22°C) until used for pollinations. Effects of time and temperature on pollen germination were investigated in culture medium with15% sucrose and 2% agarose. The germinated pollen grains were counted by using optical microscope with 10 x and the viability of them were recorded.

Results and discussion

Effects of various parameters on germination of pollen grains such as temperature and time are listed in tables 2 and 3.

Table 1. Variance analys of effects of temperature on percentage of pollen germinations of hazelnut cultivars after the stored pollen at 4 ºC and 20 ºC in deferent times.

SOV*

DF*

MS***







24 hours

5 days

10 days

20 days

cultivar

9

0.88

0.76

1.11

9.58

temperature

1

1.72

1.32

0.98

68.35

temperature *cultivar

4

0.56

0.39

1.26

3.46

E

4













total

18













*SOV: Source Variance, **DF: Degree of Freedom, * ** MS: Mean Square of measured adjectives

Results from Table 1 showed that cultivar and reciprocal effects of cultivar and temperature has no significant effect on percentage of pollen grains germinations. Therefore cultivars and temperatures have no difference on pollen grain germination in the level of 5% .in the other hand they have same effects in this level.

Table2- Variance analys of effects of deferent times of stored pollen at 4 ºC and 20 ºC on percentage of pollen germinations of hazelnut cultivars

SOV

DF

MS







4 ºC

22 ºC

cultivar

19

11.05

16.66

time

3

27.94

40.84

time *cultivar

4

22.32

37.69

E

12

3.06

3.61

total

38







Consideration in Table 2 revealed that cultivar and reciprocal effects of cultivar and time has no main effects on percentage of pollen grains germinations too. Also in the level of 5%, the time and reciprocal effects of cultivar and time have identical effects on pollen grain germination.

Table 3. Effect of cultivar on mean of germinations in several times in 4ºC



mean of germination(%)

cultivar

24 hours

5 days

10 days

20 days

Daviana

%83.93c

65.53a

41.06a

38.93a

Anbooh

66.20b

52.26b

42.06b

29.26a

Paeezeh

71.26d

48.20b

40.66b

37.20c

Tabestaneh

52.86a

51.86a

44.20a

30.06a

Asli gharebagh

58.60c

53.60c

43.26b

21.06a

For studying of effects of cultivar on average of germination on pollen grains in the various time and temperatures, data from effects of time on the cultivar in two temperatures (4 and 22 ºC) are collected in tables3 and 4.

Table 4- Effect of cultivar on average of germination in several times in 22ºC



Average of germination(%)




cultivar

24 hours

5 days

10 days

20 days

Daviana

68.98a

58.53a

21.20a

11.86a




Anbooh

61.73b

46.80b

15.80b

11.46a




Paeezeh

68.40a

44.20b

22.46a

9.33a




Tabestaneh

61.93b

55.33a

24.80a

11.66a




Asli gharebagh

62.26b

43.93b

19.93a

10.53a




Most percentages of pollen germination after 24 hours obtained in Daviana (at 22ºC) and Tabestaneh (at 4 ºC) 68.98 and 61.93 respectively. Daviana (at 22ºC) and Tabestaneh (at 4 ºC) showed most percentage of pollen grain germination of 58.53 and 65.53 respectively after 5 days. Extreme pollen germination after longer time, 10 days, attained in Asli gharebagh (at 22ºC) and Tabestaneh (at 4 ºC) 19.93and 44.20 respectively. Finally with passing 20 days from time and temperature treatment, for example Asli gharebagh at 22ºC and 4 ºC indicated percentages of pollen germination 10.53 and 21.06 respectively .Thus, at 4 ºC Asli gharebagh have best condition for germination. Quantity of pollen germination decreased with increasing time of maintenance of pollen. Results showed that pollens maintaining at 4ºC have much germination rather than 22 ºC. In the other hand, increasing the time of maintaining of pollens need to decreasing the temperatures of maintenance. Thus, 4 ºC have best condition for stored pollen germination in commercial hazelnut cultivars. Quantity of pollen germination decreased with increasing time of maintenance of pollen. Results showed that pollens maintaining at 4ºC have much germinations rather than 22 ºC. Therefore, increasing the time of maintaining of pollens need to decreasing the temperatures of maintenance.

Conclusion

In this study the pollen grains viability of five hazelnut cultivars including daviana, paeezeh, tabestaneh, asli gharebagh, and anbooh were evaluated for examination of the time of durability and the germination of pollen grains. Effects of time and temperature on cultivars and their reciprocal effects on percentage of pollen grains germinations were examined too. At 4 ºC ,asli gharebagh and tabestaneh after 20 days have Extreme pollen germination.



References

Erdouan V. and Shawn A. Mehlenbacher. 2005, Incompatibility Alleles Expressed in Pollen of Turkish Hazelnut Cultivars. Turk J, Biol 29 , 111-116

Hossin- Ava, S., Imani, A. and Makhof,M. 2006. An investigation of percentage of dichogamy and selection of the best pollinizer for commercial varieties of hazelnut. Iranian, J. Agric.Sci, Vol.37, No. 2:370-380

Johansson ,E. 1927. Floral biology trials with hazelnu at Alnarp 1924-1926 (in Swedish). Sveriges Pom Foren Arsskrift, pp. 3-20

Lagerstedt, H.B. 1975. Filberts. In: J. Janick and J.N. Moore (eds.), Advances in Fruit Breeding, pp: 456–89. Purdue University Press,West Lafayette, India

Me, G. L. , Radicati, Vallania, R., Miaja, M.L. ,Valentini, N. and Pancheri, G. 2000. Research on the genetics of incompatibility in Corylus. Acta Hort., 538: 477–81

Schuster, C.E. 1924.Filberts: 2. Experimental data on filbert pollination. Oregon Agric Expt Sta Bull No. 208: 548-555

Thompson, M.M. 1979. Incompatibility alleles in Corylus avellana L. cultivars. Theor. Appl. Genet. 55: 29-33

Thompson, M.M. 1979. Genetics of incompatibility in Corylus avellana L. Theor. Appl. Genet. 54: 113-116

Thompson, M.M., Lagerstedt, H.B. and Mehlenbacher,S.A. 1996. Hazelnut:In Janick, J. and J.N. Moore.1996. Fruit Breeding, Vol. 3. Nuts, pp:125–84. John Wiley and Sons, New York





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