Factors influencing date pollen viability

الملخص EN

Pollen of seven date cultivars was stored at 4.5 - 5.0"C using with or without silica gel and in vials outside the desicator as a control.

Germinati©n percentage was determined microscopically with a hemacytometer after harvest and at three and six months of storage, respectively, using a boric acid-sucrosc medium, c^tivar genotype did not influence the viability of pollen.

Pollen stored for six months gave a higher germination percentage (45.9%) than three months (40.9%) indicating that pollen re؟uires more than three months at 4.5 - 5"C for the reactivation of its growth factors.

An increase in relative humidi،y in storage containers resulted in reduced germination profiles.

Germination percentages were 62.2, 42.9 and 22.7% at 18, 55 and over 55 relative humidity, respectively.

Pollen stored in desiccator with and without silica gel gave a higher germination profile after six months than at three months storage whereas the control gave the lowest.

The highest germination percentage was observed in pollen kept in a desiccator in the presence of silica gel for six months.

The date palm (Phoenix dactytifera L.) is traditi©nall^ l^nd-p©llinated and requires climbing the female palm to place male strands inside the spadix.

This method has been found tedious, time consuming and costly (Ibrahim, 1988; Shabana ؛ء, al.

1986).

Changing life styles of people in areas where the date palm is grown intensively has resulted in a scarcity of skilled labour.

This situation necessitates the introduction of mechanical pollination.

The method, however, requires larger amounts of pollen in a shorter period of time than traditional techniques.

The problem is aggravated by the fact that the availability of pollen is at its lowest level during the early part of the pollination season, while large amounts are available towards the end of the season when the demand is lowest.

Consequently freshly collected pollen needs to be stored under suitable conditions so that it can be used when the demand is high.

The techniques of storing date pollen depend on the provision of low temperature and low relative humidity (Shaheen et al, 1986; Hussain et al.

1986; Yates et al.

1991).

Bukhaev et al.

(1983) reported that moisture content of fresh date pollen grown in Iraq ranges between 49.2 and 56.3%.

The moisture content of pollen prior to storage largely determines its storing