Effect of planting dates and different growing media on seed germination and growth of pistachio seedlings

Abstract

Background

Sowing time and suitable planting media are considered basic requirements to get the maximum yield and high profit for their direct and significant impact on seedlings quality and productivity of trees later. So this experiment has been carried out in a private nursery at Gharbiya Governorate, Egypt, during the seasons of 2016 and 2017 to study the effect of seven growing media (GM): sandy soil 100%; sandy soil:peat moss:vermiculite (2:1:1) by volume; sandy soil:peat moss:vermiculite (1:2:1); loamy soil:sandy soil:vermiculite (2:1:1); loamy soil:sandy soil:vermiculite (1:2:1); loamy soil:peat moss:vermiculite (2:1:1); and loamy soil:peat moss:vermiculite (1:2:1). Ashoury pistachio seeds were planted on three different dates viz, 1 February, 20 February, and 10 March and their interaction on seed germination and growth of the resulting seedlings.

Results

The results obtained from this study showed that the maximum germination percentage, number of leaves/seedling, stem diameter, root length, leaf fresh, and dry weight were recorded when the seed was planted on 10 March and seedlings growing in the loamy soil:sandy soil:vermiculite (2:1:1).

Conclusion

It could be concluded that planting seeds of “Ashoury” pistachio on 10 March in growing media contains loamy soil:sandy soil:vermiculite (2:1:1) for maximum germination and growth of subsequent seedlings.

Background

Cultivation of pistachio trees Pistacia vera L. in Egypt is very limited. It is only grown in Saint Catherine, South Sinai Governorate where the chilling requirements are sufficient. It can be grown in a variety of non-fertile, saline, and alkaline soil and in environments exposed to varying periods of drought stress (Sheibani 1994). The increased consumption of pistachio nuts may be attributed to their high nutrient components, including sterols, vitamins, minerals, fatty acids, and phenolic compounds (Yang et al. 2009), and thus may be considered as “unique functional food” and recently classified among the top 50 food products highest in antioxidant potential (Halvorsen et al. 2006).

The convenient sowing time of each type of crop is considered basic requirements to yield. A number of experiments have been conducted on sowing seeds and transplanting time, which showed that the total crop yield is significantly affected by sowing times (Snoek 1981). Moreover, the use of suitable growing media or substrates for sowing seeds directly affects the germination, development, and functional rooting system (Meena et al. 2017).

A good growing media provides adequate anchors or support to the plant, a reservoir for nutrients and water allows the release of oxygen to the roots and gas exchange between the roots and the atmosphere outside the roots substrate (Abad et al. 2002). The quality of seedlings is greatly affected by the growth media under nursery (Agbo and Omaliko 2006). The quality of the seedlings obtained from a nursery affects the re-establishment in the field and the final productivity of the orchard (Baiyeri and Mbah 2006).

Soil, peat moss, and vermiculite are generally used as a basic medium for sowing seeds in nurseries because it is cheap and easy to procure supplementing the soil to make media more porous and adequate source to the nutrients for the seedlings. Additionally, vermiculite has been used for years to amend professional potting soils made from peat moss (called “soilless” mixes or artificial soils because they literally contain no soil) (Meena et al. 2017). Essentially, vermiculite is used in the horticultural industry because it provides aeration and drainage, it can retain and hold a substantial amount of water and later release it as needed, it is necessary to find out proper planting date for sowing of Ashoury pistachio seeds in nursery as the farmers can obtain good earning by producing these seedlings. The present study was carried out to explore the most suitable date and growing media of sowing for Ashoury pistachio seeds in nursery.

Materials and methods

Mature seeds of Pistacia vera L. cv. ‘Ashoury’ were obtained from pistachio orchard in Saint Catherine, South Sinai, Egypt. The experiments were conducted in a private nursery at Gharbiya Governorate during two growth seasons (2016 and 2017) and data was represented as the average of two seasons. Seven growing media (GM): sandy soil 100% (GM1); sandy soil:peat moss:vermiculite (2:1:1) (GM2) by volume; sandy soil:peat moss:vermiculite (1:2:1) (GM3); loamy soil:sandy soil:vermiculite (2:1:1) (GM4); loamy soil: sandy soil: vermiculite (1:2:1) (GM5); loamy soil:peat moss:vermiculite (2:1:1) (GM6); and loamy soil:peat moss:vermiculite (1:2:1) (GM7). Physical and chemical properties of these growing media are shown (Table 1). Ashoury pistachio seeds were planted on three different dates viz, 1 February, 20 February, and 10 March at 20 days interval in polythene bags (60 × 25 cm) after soaking in water for 36 h (Abou Rayya et al. 2018). Each growth medium was represented by 10 polythene bags per replicate and replicated three times. One seed was sown per bag after disinfected by a fungicide and irrigation with water daily. In addition to this, all other cultural practices were completed according to the requirements of nursery. The experiment was ended on September 2016 and 2017, germination percentage of pistachio seeds was measured as number of seeds that produced a seedling from each seeds group and expressed as percentage) according to (Al-Imama and Al-Jubury 2011), the stem length, number of leaves/seedling, leaf area, stem diameter of 5 cm above the soil surface, root length, leaf fresh weight, leaf dry weight, stem fresh weight, stem dry weight, root fresh weight, and root dry weight were measured for all plants. Data were statistically analyzed using completely randomized design with two factors with three replicates (10 seeds per replicate). Analysis of variance and Duncan’s multiple range tests were used (Roger and Hasted 2003).

Table 1 Physical and chemical properties of the growing media

Results

Germination seeds

The germination percentage of pistachio seeds was significantly affected by the planting date and medium (Table 2). The maximum germination (25.43%) was observed under sowing in 10 March. However, the minimum germination (22.57%) was recorded in 1 February sowing. Pistachio seeds were sowing in the (GM4) contained loamy soil: sandy soil: vermiculite (2:1:1) gave the highest germination percentage (26.33%). While the sowing in the (GM1) contained sandy soil 100% gave the lowest germination percentages (21.33%).

Table 2 Effect of planting dates and different growing media and the interactions between them on seed germination percentage of pistachio seedlings

Seedling stem length

The maximum of seedling stem length (47.41 cm) was recorded with sowing on 20 February; however, the minimum of seedling stem length (38.87 cm) was noted when seeds were sown on 1 February. Growing media (GM4) loamy soil: sandy soil: vermiculite (1:2:1) was recorded the highest stem length (53.03 cm). The lowest stem length was (30.51 cm) in 100% sandy soil (Table 3).

Table 3 Effect of planting dates and different growing media and the interactions between them on stem length and number of leaves/seedling of pistachio seedlings

Number of leaves/seedling

The higher number of leaves/seedling (28.90) was noted when planted pistachio seeds on 10 March. The early planting (1 February) of pistachio seeds had lower number leaves/seedling (20.81). The greatest number of leaves/seedling (30.89) was found with loamy soil:sandy soil:vermiculite (1:2:1) and the least number of leaves/seedling (18.22) was found on 100% sandy soil (Table 3).

Leaf area

The maximum leaf area (7.17 cm²) was recorded in the seeds sown on 20 February. The minimum leaf area (6.71 cm²) was recorded in the seeds sown on 10 March (Table 4). The highest leaf area (7.75 cm²) was observed with planting in the loamy soil:sandy soil:vermiculite (1:2:1) and the lowest leaf area (6.20 cm²) with planted in100% sandy soil.

Table 4 Effect of planting dates and different growing media and the interactions between them on leaf area of pistachio seedlings

Stem diameter

The greater stem diameter (4.19 mm) was recorded when planted on 10 March (Table 4). The early sowing (1 February) recorded a minimum stem diameter (3.23 mm). Growing media (GM6) loamy soil:peat moss:vermiculite (2:1:1) was recorded the highest stem diameter (4.58 mm). The lowest stem diameter was (2.93 mm) in 100% sandy soil (Table 5).

Table 5 Effect of planting dates and different growing media and the interactions between them on stem diameter and root length of pistachio seedlings

Root length

The maximum root length (34.40 cm) was recorded with sowing on10 March; however, the minimum root length (29.53 cm) was noted when seeds of pistachio were sown on 1 February (Table 4). The highest root length (39.58 cm) was found in seedlings growing in the (GM4) contained loamy soil:sandy soil:vermiculite (2:1:1) (Table 4). Whereas, the seedlings growing in the (GM1) contained sandy soil 100% were recorded the lowest root length (22.71 cm) (Table 5).

Leaf fresh and dry weight

It is obvious from Table 6 that leaf fresh and dry weight of pistachio seedlings were significantly affected by the planting dates and different growing media. Sowing seeds on10 March in (GM4) loamy soil:sandy soil:vermiculite (2:1:1) was recorded the highest values (15.70 and 17.63; and 6.24 and 6.98 gm), respectively. While the early sowing seeds on 1 February in sandy soil, 100% was recorded the lowest values (14.72 and 12.49; and 5.80 and 4.95 gm), respectively.

Table 6 Effect of planting dates and different growing media and the interactions between them on leaf fresh and dry weight of pistachio seedlings

Stem fresh and dry weight

Results in Table 7 indicated that stem fresh and dry weight of Ashoury pistachio seedlings influenced significantly as a result of the planting dates and different growing media. The maximum stem fresh and dry weight were recorded with sowing on 20 February in (GM4) loamy soil:sandy soil:vermiculite (2:1:1) (10.79 and 13.22; and 3.29 and 3.93 gm); however, the minimum stem fresh and dry weight (8.58 and 5.84; and 2.68 and 1.65 gm) were noted when seeds were sown on 1 February in sandy soil 100%, respectively.

Table 7 Effect of planting dates and different growing media and the interactions between them on stem fresh and dry weight of pistachio seedlings

Root fresh and dry weight

Results in Table 8 show that root fresh and dry weight were significantly affected by the planting dates and different growing media. Sowing seeds on 20 February in (GM4) loamy soil:sandy soil:vermiculite (2:1:1) was recorded the highest values (7.82 and 10.60; and 3.37 and 4.41 gm), respectively. While the early sowing seeds on 1 February in sandy soil 100% was recorded the lowest values (7.06 and 5.28; and 2.84 and 1.70 gm), respectively.

Table 8 Effect of planting dates and different growing media and the interactions between them on root fresh and dry weight of pistachio seedlings

Discussion

To determine the suitable planting date and agricultural soil for production of Ashoury pistachio seedlings in nursery, were compared between three planting dates: 1 February, 20 February, and 10 March with seven agricultural medias:sandy soil 100%; sandy soil:peat moss:vermiculite (2:1:1); sandy soil:peat moss:vermiculite (1:2:1); loamy soil:sandy soil:vermiculite (2:1:1); loamy soil:sandy soil:vermiculite (1:2:1); loamy soil:peat moss:vermiculite (2:1:1), and loamy soil:peat moss:vermiculite (1:2:1). The maximum germination percentage, number of leaves/seedling, stem diameter, root length, leaf fresh, and dry weight were recorded when the seed was planted on 10 March and seedlings growing in the (GM4) contained loamy soil:sandy soil:vermiculite (2:1:1). This increase in germination percentage could be attributed to favorable soil temperature 15–18 °C and optimum moisture at the sowing time which caused an increase in germination percentage and contributes seedling production at the desired level. The optimum temperature is the basic requirement for germination (Hall 1975).

The increase in seedlings growth recorded in this investigation could be a reflection of the effect of the combination of high moisture retention and significant air space in agricultural media. The results are in agreement with those obtained by (Al-Imama and Al-Jubury 2011). In addition, growth media (GM4) contained adequate nutrients and the high water retention capacity necessary for germination and growth of pistachio seedlings. Results are in line with those published by (Okunomo et al. 2009).

These results are in conformity with the findings of (Lucas and Davis 1961) who observed that a pH close to neutral is suitable for most container-grown woody shrubs and trees to supply available nutrients in adequate quantities for cell turgidity and enlargement within plant tissues.

These results are also in agreement with observations of (Poole and Conover 1982; Hassan et al. 1994) that peat moss and loamy soil increased nutrient retention, promoted vegetative growth, and improved growth overall through the activity of meristematic tissue (Kramer and Koziowski 1979). Comparing all agricultural media and planting dates.

Conclusion

Finally, it can be concluded that planting seeds of “Ashoury” pistachio on 10 March in growing media contains loamy soil:sandy soil:vermiculite (2:1:1) fulfillment maximum germination and enhance growth of subsequent seedlings.