Observation And Study On The Main Biological Characteristics Of The Twenty-one Macadamia Germplasms

Macadamia nuts, a kind of evergreen fruit tree originated in Australian, is an emerging upscale nut tree species. So far, the systemic observation on the phenophase, botanical characteristics of different macadamia resources is still limited. For laying the foundation of the field management and the collection and identify of germplasm resources in macadamia, we used 21 germplasms of macadamia in Zhanjiang area to observe and study their phenophase and botanical characteristics respectively. The results were showed as follows:(1) Experimental macadamia germplasms can grow shoots for 3 or 4 times/year, including spring shoots, summer shoots and autumn shoots. Spring shoots bud in late January, stabilizing from late March to early May. Duration of spring shoots is various in different germplasms, at the same time, it could be concerned with air temperature changes from January to February when it growing. Summer shoots bud from late April to early May, stabilizing from late June to early July. Autumn shoots bud only once in one year for most germplasms from late June to early July, stabilizing from late August to early December. However,’Yonik’,’A4’,’922’,’783’,’814’, and ’695’ could bud twice, the first one bud in early May, and the second from July to August. Different germplasms autumn shoots display a marked difference. In the process of shoots growth, color of shoots of all germplasms turns from light red to green and to brown at last, and that of new leaves are from light red to green with 3 leaves grown at the every joint of shoots on the avarage, while new leaves color, new shoots length, the number of joint and intermodal length display a unconspicuous difference in various germplasms.(2) Flowering phenophase varies performances from 21 germplasms.’Nanya No.1’ is the earliest blooming germplasm, and the next is ’24’. They are both early blossoming germplasms. While ’116’ and ’695’ are the latest and belong to late blossoming germplasms, and others flowers budding in late January. Spica born period of 7 germplasms is more than 45 days, namely,’Nanya No.1’,’24’,’Own venture’,’A4’,’B’,’D’ and ’695’, and others is about 35-45days. Except ’695’ complete flowering and defeating in early April, others flowering concentrate in early March and defeating in late March, duration is various in different germplasms. Most Macadamia gennplasms only flower once, while some germplasms could flower 2-3 times such as ’O.C.’, and ’A4’. Different germplasms have diverse starting and ending time in flowering, and flowering times is also different.(3) ’333’ has the earliest fruit time and ’695’ the latest one in experimental germplasms, while others are in late March. Different experimental germplasms have various speedy-grown periods about 50-70 days. Most germplasms oil accumulation period is from late May to late August, about 80-100 days. In fruit maturity, the earliest one is ’Nanya No.1’ while the latest one still is’695’. Most germplasms fruit maturity is from late August to mid September.(4) Limb crotch angle is acute for all experimental germplasms; the main trunk is rough; tree performance is half-opened; and tree form is semicircle.(5) Most germplasms leaves are dark green, oblanceolate, foliage apex and foliage base are both sharp acuminate, leafedge is obvious wave and thorns in leafedge is loose, foliage surface is inturned, stipe length is from 0.7-1.3cm, foliage length is from 10 to 15cm, and width is from 3.4 to 4.2. Some germplasms have unique foliage identification features, as’H2’ foliage is oval and foliage apex is blunt form,’A’foliage apex is sharp acuminate and foliage base is curved shapes, while’A4’has the most intensive leafedge thorn and the shortest stipe.(6) Most experimental germplasms flower color is ivory or flaxen, flower length is from 12 to 20cm, floret number is more than 150 and density is from 10 to 13 each square centimeters. Most germplasms have no the phenomenon of more bloom times. All germplasms flowering order is from base to top, and pollen grain shape is triangle. Some germplasms have unique flower morphology, for example,’Nanya No.3’has a long flower, with a large number of florets and small density, while flower of’B’ is short with large density, and flower of’695’is pink.’814’,’B’,’A4’,’O.C.’,’Nanya No.1’,’Nanya No.2’have the phenomenon of more bloom times.(7) Most fruits are oval, smooth and spring green among 21 germplasms, their weight ranges from 15 to 20g, ventral suture is not obvious, fruit stem and protuberance of shoot is obvious, and carpopodium is skew and length is from 3.0 to 4.5mm. Most experimental germplasms nut-inshell is oblate, smooth, weight is from 5.0 to 8.0g, ventral suture is obvious, speckle distribute dispersedly, micropyle is closed, hilum is small and have a small pit, and shell thickness is more than 2.0mm. Kernel color is oyster, their weight is from 2.0 to 3.0g, kernel ratio is from 31 percent to 37 percent, and the first class nut rate is from 88% to 98%. Some germplasms have unique features, for example,’Nanya No.2’protuberance of shoot is extremely obvious, speckle of ’788’ distribute in the middle of nut-inshell, while speckle of ’344’ in the base, ’783’ has extremely obvious ventral suture, and ’Nanya No.1’ is open.