Climatically Optimum Growth Areas Papaya Composite Of All Criteria

Papaya, or pawpaw (Carica papaya) is a tropical fruit grown widely between latitudes 32 degree N and S. High in Vitamin C, papaya is indigenous to tropical America (ARC, 2005). This fruit, initially brought to the attention of Europe around 1520, was introduced to South Africa in seed form by Jan van Riebeeck in 1652, but only grown commercially in the Lowveld of Mpumalanga for the first time in the early 20th century by a Captain Elphick (ARC, 2005). Papaya needs relatively little water in the rainy summer season in South Africa, but if irrigated every 2 weeks in the dry season it is well adapted to hot, dry areas as the fruit then matures early and is then highly palatable owing to its high sugar content (Smith, 1998). Papaya has high heat requirements, with average daily temperatures for optimum growth between 20 and 30 degree Celsius. Determination of climatically optimum growth areas for Papaya in South Africa is based on the expert knowledge of Bower (2005) and Moll (2005), climatically optimum growth areas were determined according to the four basic criteria: Criterion 1: Heat units (base 12 degree Celsius) should exceed 2 000 days per annum, Criterion 2: Optimum areas should have a low frequency of 4 consecutive days with maximum temperatures > 36 degree Celsius, Criterion 3: Monthly means of daily average temperatures in December and January should be 23 degree Celsius - 30 degree Celsius and Criterion 4: Optimum growth areas should have a low frequency of 4 consecutive days with minimum temperatures < 17 degree Celsius. Using the 50 year time series of quality controlled daily maximum and minimum temperatures generated by Schulze and Maharaj (2004) at a spatial resolution of 1 arc minute (i.e. 1` x 1` of a degree latitude/longitude), the above four temperature based criteria were first mapped individually and then superimposed to determine the climatically optimum growth areas of papaya in South Africa.

番木瓜（Papaya，又名pawpaw，学名*Carica papaya*）是一种广泛种植于南北纬32度之间的热带水果。其维生素C含量丰富，原产于热带美洲（ARC, 2005）。该果品约于1520年首次传入欧洲视野，1652年由扬·范里贝克以种子形式引入南非，但直至20世纪初，才由埃尔菲克上尉在姆普马兰加省低草原地带（Lowveld）开展首次商业种植（ARC, 2005）。在南非，番木瓜在多雨的夏季需水量相对较少；若在旱季每2周灌溉一次，则可良好适配炎热干旱的气候环境——此时果实早熟，且因糖分含量高而口感极佳（Smith, 1998）。番木瓜对热量需求较高，适宜生长的日均温区间为20℃至30℃。南非番木瓜气候适宜种植区的划定，依托鲍尔（Bower, 2005）与莫尔（Moll, 2005）的专业研究经验，基于四项核心判定标准：标准1：以12℃为基准的年累计热量单位需超过2000日度；标准2：连续4天最高气温＞36℃的发生频率较低；标准3：12月与1月的日均温月均值应处于23℃至30℃之间；标准4：连续4天最低气温＜17℃的发生频率较低。本研究采用舒尔茨与马哈拉吉（Schulze and Maharaj, 2004）生成的50年质量控制日最高、最低气温时间序列，其空间分辨率为1弧分（即1′×1′经纬度），先分别绘制上述四项基于气温的判定标准分布图，再通过叠加分析得到南非番木瓜的气候适宜种植区。