By Tony Jimenez LONDON, April 21 (Reuters) - With more and more part-timers finding they have less time for 18-hole golf lasting upwards of four hours, a shorter form of the sport could give the amateur game the shot in the arm it desperately needs. Hoping perhaps to have the same galvanising effect on golf as the Twenty20 explosion has had on cricket interest, British Open organisers the R&A decided to take a lead this week by launching a new nine-hole event to be played at Royal Troon. To further indicate the growing interest in the shorter form of the game, the prize fund for the Farmfoods British Par-3 Championship in Warwickshire, hosted by Tony Jacklin from July 26-29, has risen by 20 percent to a record 150,000 euros ($169,170). More...