Peach Seed Germination and the Effect of Stratification Thereof. Grant Goldstein Texas A&M University, Student of Agriculture, Department of Horticulture, 495 Horticulture Street, College Station, TX Word index: Prunus persica, gibberellic acid, GA3, Cold moist stratification, warm moist stratification, breaking dormancy, physiological dormancy, Endocarp, Angiosperm Abstract: Study the different effects that cold, moist stratification time lengths and the application of gibberellic acid, doubled by the presence or absences of the endocarp have on the germination rate of the Prunus persica (peach) seeds. The removed endocarp set had statistically significant advantage over the intact endocarp set. Introduction: Angiosperms as flowering plants have an advantage of reproduction by seeds, allowing stored energy to translate into a higher percent germination, beyond just using stored energy is the use of delayed germination. Germination will occur when environmental and physiological conditions are most favorable to the seed/seedling’s survival. This period before germination is termed dormancy. Favorable condition to end dormancy, which is often called breaking dormancy, may take years depending on the species as well as its environment. Man has studied dormancy and its breaking to better and quicker cultivate species. In the case of our studied material, Prunus persica, the presence or absence of the seed’s endocarp, a hard tissue layer surrounding the seed, has a significant role the seed’s germination percentage in the following study.

Materials and methods: Prunus persica, commonly known by peach, was the seeds used. Eighty seeds, 10 for each condition. Half of the seeds had their endocarps removed while the other half remained intact. Ten seeds each from both the intact and removed endocarp were set aside as there control treatment. Two sets of ten seeds each from both the intact and removed endocarp, 40 seeds total, underwent cold moist stratification at a temperature of 4°C with high humidity for 3 weeks or 12 weeks placed in Ziplock bags with perlite. Ten seeds each from both intact and removed endocarp were immersed in 3000 ppm Gibberellic Acid (GA) solution for 24 hours while aerated by aquarium pumps.

A jiffy tray was filled with 50/50 peat:perlite mix, seeds were placed into potting mix ¾-1 inch deep into rows space ½ inch apart with rows spaced at 1 ½ inch. The experiment was initiated on February 5, 2015. Jiffy tray was place in Horticultural greenhouse and water 2-4 days as needed. Observations of percentage germination and general characteristic were recorded weekly from the initiation. Results and Discussion: Observations recorded weekly after starting procedure. Fig. 1 displays the data from one repetition conducted. At the first observation, only 1 seed, the 12-week no endocarp (-), had germinated. By week 2, a total 14 seeds had germinated, 3 3-weeks (-), 5 12-week (-), 1 12week (+), 4 GA 3000ppm (-). This is the largest percent change of germination in this repetition data set. Week 3 would see 6 new seedlings emerge from between the 3-week (-) and the GA (). Later weeks saw 1 to 2 new germinating seedlings but no new seedlings after week 4. % Emergence/ (Weeks)

Section data 503

Whole Class Data

Treatment

1

2

3

4

5

6

7

8

Control no endocarp

0

0

0

0

0

0

0

0

0%

0

13.3

10.7

Control with endocarp

0

0

0

0

0

0

0

0

0%

0

0

0

Strat, 3wks no endocarp

0

3/ 6/ 6/ 6/ 6/ 6/ 6/ 10 10 10 10 10 10 10

60%

25.26

50

25.9

Strat, 3wks with endocarp

0

0

0

0%

0

0

0

Strat, 12wks no endocarp

1/ 10

6/ 6/ 7/ 8/ 8/ 8/ 8/ 10 10 10 10 10 10 10

80%

26.58

70.6

34.2

Strat, 12wks with endocarp

0

1/ 1/ 1/ 1/ 1/ 1/ 1/ 10 10 10 10 10 10 10

10%

31.5

21.1

27.3

0

0

0

0

0

Final Final Observations Final Final % Avg. % Avg. Germ Height Germ Height

GA 3000 ppm no endocarp

0

4/ 7/ 7/ 8/ 8/ 8/ 8/ 10 10 10 10 10 10 10

80%

17.05

GA 3000 ppm with endocarp

0

0

0%

0

0

0

0

0

0

0

one dead

59.4

20.8

4.4

4.3

Table 1

Table 2 represents the cumulative data from the 18 total repetitions with final germination in a percentage and final average height in centimeters. The superscript letter(s) represents the data comparable honest significant statistical difference. This means that within the same column, a treatment’s germination percent or average height may be compared with another treatment, if the superscript is same or contains the same letter; the significant difference is low enough so that difference between the treatments is insignificant. The significance of this ‘insignificance’ is that some treatments are not comparably better due to their variance yet have different average values. This can be demonstrated by comparing the Intact endocarp treatments of control, GA, and 3-week stratified. Intact control and 3-week both had an average of 0% and GA had a 4.4% germination rate but the variance for the GA was high enough that the probability value nullifies the treatment’s cause and effect by assuming the germination that did occur happened by random chance. Equating to the intact control, GA, and 3-week treatments having similar result no germination. Table 2 demonstrates that the removed endocarp 12-week stratification had the best germination at 70.6% combined with the tallest average height at 34.2cm, healthy color, vigorous foliage in size with comparatively longer internodes within Group 4’s repetition. The removed endocarp GA soak treatment came in with the second best germination rate of 59.4% and an average height of 20.8cm, also having healthy color but shorter internode lengths and leaf size than that of other treatments. Third greatest, endocarp removed 3-week stratification with 50.0% germination and 34.2cm

Table 2 represents the average of the 18 repetitions

Endocarp

Pre-germination treatment

Final Germination (%)

Final Average Height (cm)

Intact (+)

Removed (-)

Control

0

0

GA 3000 ppm

4.4

4.3

Stratification 3 weeks

0

0

Stratification 12 weeks

21.1

C

27.3

AB

Control

13.3

CD

10.7

C

GA 3000 ppm

59.4

AB

20.8

B

Stratification 3 weeks

50.0

B

25.9

AB

Stratification 12 weeks

70.6

A

34.2

A

D

D

D

d

D

D

Table 2 with total order from least to greatest being; (+)control, (+) 3weeks, (+) GA3000ppm, (-)control, (+) 12 weeks, (-) 3 weeks, (-) GA3000ppm, (-) 12 weeks